The Consumer Price Index (based on a value of 100 in 1986) rose from 67.2 in 1980 to 119.5 in 1990. What was the (equivalent) annual rate of inflation in the decade of the 1980s?

Annual Rate of Inflation

the percent increase in the price level of goods and services across the economy over the course of a year.

Consumer Price Index

A measure that examines the weighted average of prices of a basket of consumer goods and services, such as transportation, food, and medical care, typically used to monitor inflation.