Why did the U.S. Consumer Price Index become pseudolinear after 1980?

Question

I’m an econ college student, and I just can’t wrap my head around it. An inflation index should be exponential, and it looks like it is until 1980, then it just…planes off. In order for a linear CPI to make sense, inflation would have to be constantly decreasing and that just doesn’t make any sense to the experience of the average consumer.

Edit: here’s the series in question.
https://fred.stlouisfed.org/series/CPIAUCSL

In: Economics

Answer 1

> inflation would have to be constantly decreasing

Inflation has been constantly decreasing. If you look at the average inflation by decade you get:
80’s = ~5.5%
90’s = ~3%
00’s = ~2.5%
10’s = ~2%