-81.78% is the change from 664 to 121
Calculation steps:
[( 121 - 664 ) ÷ 664] x 100 = -81.78%
Formula
Percentage change = [(121 - 664) / 664] x 100
Subtract the new number by the original number
121 - 664 = -543
-543 ÷ 664 = -0.8177710843373494
-0.8177710843373494 x 100 = -81.78%