Average annual rate of change (percent change)

In Health, United States, average annual rates of change, or growth rates, are calculated as:

$[{(P_{n} / P_{0})}^{1 / N} - 1] \times 100$

where

P_n = later time periodP_o = earlier time periodN = number of years in interval.

This geometric rate of change assumes that a variable increases or decreases at the same rate during each year between the two time periods.