The CPI takes a constant basket of goods and sees how the price changes from year to year. If the price of the basket of goods increases, then there is price inflation. If the price of the basket of goods decreases, then there is deflation.
Copper and tin mainly make up bronze but other elements include phosphorus, manganese, silicon and aluminium.
This metal is neither precious nor pure being primarily an alloy of different metals, copper and tin, but may be made with other metals such as zinc, aluminium or nickel. However good quality bronze was highly prized for its strength and durability.