-15.46% is the change from 970 to 820
Calculation steps:
[( 820 - 970 ) ÷ 970] x 100 = -15.46%
Formula
Percentage change = [(820 - 970) / 970] x 100
Subtract the new number by the original number
820 - 970 = -150
-150 ÷ 970 = -0.15463917525773196
-0.15463917525773196 x 100 = -15.46%