This statistic shows the unadjusted annual inflation rate in the U.S. from 1990 to 2012. The data represents U.S. city averages. The base period was 1982-84. In economics, the inflation rate is a measure of inflation, the rate of increase of a price index (in the below case: consumer price index). It is the percentage rate of change in price level over time. The rate of decrease in the purchasing power of money is approximately equal. In 2012, prices went up by 2.1 percent compared to the previous year.