Consumer price index
The consumer price index (CPI) is a way of measuring the overall price level of the consumer goods and services in the economy. It is found by tracking the price of a market bundle, which is a list of certain goods in certain amounts. By seeing how the prices of all the goods together change between years, economists can measure inflation.
Consumer Price Index Media
A graph of the US CPI from 1913 (in blue), and its percentage annual change (in red)
Inflation compared to federal funds rate
CPI vs PCE