Historic prices for currencies, commodities,
My guess it's a legal agreement between Yahoo and data provider on what data can be stored, displayed and for how long. Check out this list of data providers
Gold isn't constant in value. If you look at the high price of $800 in January of 1980 and the low of $291 in 2001, you lost a lot of purchasing power, especially since money in 2001 was worth less than in 1980. People claim gold is a stable store of value but it isn't. No. The long-term valuation of currencies has to do with Purchasing Power Parity.  The long-term valuation of stocks has to do with revenues, expenses, market sizes, growth rates, and interest rates. In the short term, currency and stock prices change for many reasons, including interest rate changes, demand for goods and services, asset price changes, political fears, and momentum investing.  In any given time window, a currency or stock might be: The Relative Strength Index tries to say whether a currency or stock has recently been rising or falling; it does not inherently say anything about whether the current value is high or low. "During Graham's career, gold and currency were the same thing because of the gold standard. Graham did not advise investing in currencies, only in bonds and stocks, the latter only for intelligent speculation. Graham died a couple of years after Nixon closed the gold window, ending the gold standard.  Gold may be thought of as a currency even today, as endowments and other investors use it as a store of value or for diversification of risks. However, currency or commodities investing does not seem Graham-like. How could you reliably estimate intrinsic value of a currency or commodity, so that you can have a Graham-like margin of safety after subtracting the intrinsic value from the market value?  Saying that gold is ""clearly underpriced in today's market"" is just hand-waving. A Graham analysis such as ""net net"" (valuing stocks by their current tangible assets net of all liabilities) is a quantitative analysis of accounting numbers audited by CPAs and offers a true margin of safety." "The relative value of Gold (or any other commodity) as measured against any given currency (such as the USD), is not a constant function either. If you have inflationary pressure, the ""value"" of an ounce of gold (or barrel of oil, etc) may ""double"", but it's really because the underlying comparator has lost ""half"" its value." I commented about oil in response to u/timothyblomfield. I know way more about oil than any other commodities.   But steel is another heavily scrutinized commodity. All the talk of China importing illegal steel, people losing steel jobs, etc. Commodities become important like this when international politics become involved. I can't think of any specifically, but if you haven't already done so it would be worthwhile reading a textbook on macro-economics to get an idea of how money supply, exchange rates, unemployment and so on are thought to relate.   The other thing which might be interesting in respect of the Euro crisis would be a history of past economic unions. There have been several of these, not least the US dollar (in the 19C, I believe); the union of the English and Scottish pound (early 1600s); and the German mark. They tend to have some characteristic problems, caused partly by different parts of the union being at different stages in an economic cycle. Unfortunately I can't think of a single text which gathers this together. Look into commodities futures & options. Unfortunately, they are not trivial instruments. Yes, this phenomenon is well documented.  A collapse of an economy's exchange rate is coincidented with a collapse in its equities market.    The recent calamities in Turkey, etc during 2014 had similar results. Inflation is highly correlated to valuations, and a collapse of an exchange rate is highly inflationary, so a collapse of an exchange rate is highly correlated to a collapse in valuations. The Federal Reserve Bank publishes exchange rate data in their H.10 release. It is daily, not minute by minute. The Fed says this about their data: About the Release The H.10 weekly release contains daily rates of   exchange of major currencies against the U.S. dollar. The data are   noon buying rates in New York for cable transfers payable in the   listed currencies. The rates have been certified by the Federal   Reserve Bank of New York for customs purposes as required by section   522 of the amended Tariff Act of 1930. The historical EURUSD rates for the value of 1 EURO in US$ are at: http://www.federalreserve.gov/releases/h10/hist/dat00_eu.htm If you need to know USDEUR the value of 1 US$ in EUROS use division 1.0/EURUSD. There are two ways to measure the value of money in the past. 1) As Victor mentioned there are inflation statistics covering the last 100 or so years that value the currency against an ever-changing basket of goods. This is sufficient when measuring general inflation over the period of the hundred years where there is data. This is how it was measured in your example. 2) For older time periods or where a value comparison is required between specific items (particularly where these were not in the basket of goods used for the inflation calculation) Historical records of the price of comparable goods can be used. This is in effect the same as mark to market valuations for illiquid financial instruments and requires poring through records to find the price of either a comparable basket of goods to one that would be used for inflation calculations today or a comparable set of items. An example of this is finding the value of a particular type of house (say a terraced house in London) in the 19th Century compared to the same house today by finding records of how much comparable houses would sell for, on average, then and now. This second measure is also used where the country in question didn't or doesn't keep reliable inflation statistics which may well be true of Colombia in the 90s. This means that there is a chance that this way of estimating Escobar's wealth in today's terms may have also been used. Another notable reason to use this methodology is that (unless you are using exchange rates in purchasing power parity terms) the value of money held in different currencies is different. This is even true today as the value of $1 in INR in India is likely to be higher than the value of a dollar in the US in terms of what you can buy. Using this methodology allows for a more accurate comparison in values where different countries and currencies are involved. Hey thanks for your response.  The commodity is actually electricity, so definitely not able to store.  Would you mind giving me a short summary of your thought process or an example of how you compare liquid markets vs illiquid ones when looking at more traditional commodities?  If that is a bit much to ask, as I am sure it could get quite involved do you have any reading recommendations?    This little project has sparked an interest. You will most likely not be able to avoid some form of format conversion, regardless of which data you use since there is, afaik, no standard for this data and everyone exports it differently. One viable option would be, like you said yourself, using the free data provided by Dukascopy. Please take into consideration that those are spot currency rates and will most likely not represent the rate at which physical and business-related exchange would have happened at this time. Inflation can be held at whatever level the international fiat banking system desires up until it hits the tipping point. Commodities are still high over a 3 year tracking (my uncle and cousin run a family farm of 1000 acres and they are in heaven this year with prices of beef, corn, and soy so high), and luxury goods are deflating because no one is buying them. For press releases about economic data, the Bureau of Economic Analysis press release page is helpful. Depending on the series, you could also look at the Bureau of Labor Statistics press release page.  For time series of both historical and present data, the St. Louis Federal Reserve maintains a database such data, including numerous measures of GDP, called FRED. They list nearly 15,000 series related to GDP alone. FRED is extremely useful because it allows you to make graphs that indicate areas of recession, like this:  On the series' homepage, there's a bold link on the left side to download the data. If you simply need the most recent data, it's listed below the graph on that page.  If you're interested in a more in-depth analysis, you can use the Bureau of Economic Analysis as well, specifically the National Income and Product Accounts, which are most of the numbers that feed into the calculation of GDP. FRED also archives some of these data. Both FRED and the BEA compile data on numerous other economic benchmarks as well.  Other general sources for a wide range of announcements are the Yahoo, Bloomberg, and the Wall Street Journal economic calendars. These provide the dates of many economic announcements, e.g. existing home sales, durable orders, crude inventories, etc. Yahoo provides links to the raw data where available; Bloomberg and the WSJ provide links to their article where appropriate. This is a great way to learn about various announcements and how they affect the markets; for example, the somewhat disappointing durable orders announcement recently pushed markets down a few points.  For Europe, look at Eurostat. On the left side of the page, they list links to common data, including GDP. They list the latest releases on the home page that I previously linked to.  For the sake of keeping this question short, I'm lumping the rest of the world into this paragraph. Data for many other countries is maintained by their governments or central banks in a similar fashion. The World Bank's databank also has relevant data like Gross National Income (GNI), which isn't identical to GDP, but it's another (less common) macroeconomic indicator.  You can also look at the economic calendar on livecharts.co.uk or xe.com, which list events for the US, Europe, Australasia, and some Latin American countries. If you're only interested in the US, the Bloomberg or Yahoo calendars may have a higher signal-to-noise ratio, but if you're interested in following how global markets like currency markets respond to new information, a global economic calendar is a must. Dailyfx.com also has a global economic calendar that, according to them, is specifically geared towards events that affect the forex market.  As I said, governments and central banks compile a lot of this data, so to make searching easier, here are a few links to statistical agencies and central banks for major countries. I compiled this list a while ago on my personal machine, so although I think all the links are accurate, leave a comment if something isn't quite right.  Statistics Australia / Brazil / Canada / Canada / China / Eurostat / France / Germany / IMF / Japan / Mexico / OECD / Thailand / UK / US Central banks Australia / Brazil / Canada / Chile / China / ECB / Hungary / India / Indonesia / Israel / Japan / Mexico / Norway / Russia / Sweden / Switzerland / Thailand / UK / US FYI...prices don't always go up.  Inflation is a monetary phenomenon.  I'm simplifying greatly here: if more money is printed (or the money supply increases through fractional reserve banking) and it is chasing the same amount of goods then prices will go up.  Conversely, if money is held constant and the economy becomes more productive, producing more goods, then a constant amount of money is chasing an increasing amount of goods and prices go down. After the Civil War the greenback went back to being on a gold standard in 1879.  After 1879 greenbacks could be redeemed for gold.  Gold restricts money growth since it is difficult to obtain. Here are the price and wage indexes from 1869 - 1889 (from here):  Notice from 1879 to 1889 that wholesale and consumer prices fall but wages start to increase.  Imagine your salary staying the same (or even increasing) but the prices of items falling. Still don't think inflation is a monetary phenomenon?  Here is a CPI chart from 1800 to 2007:  Notice how the curve starts to go drastically up around 1970.  What happen then?  The US dollar went off the gold-exchange standard and the US dollar became a purely fiat currency backed by nothing but government decree which allows the Federal Reserve to print money ad nauseum.