Joshua Kennon, author of The Complete Idiot's Guide to Investing, 3rd Edition , discusses this topic in more detail in an article posted to his blog in September 2011. This means an increasing number of Americans are joining the ranks of the rich and the upper middle class. He found that the number of households earning $350,000 or more a year (adjusted for inflation) increased eighteen times, from 0.1% of the population in 1979 to 1.8% in 2014.