-31.09% is the change from 936 to 645
Calculation steps:
[( 645 - 936 ) ÷ 936] x 100 = -31.09%
Formula
Percentage change = [(645 - 936) / 936] x 100
Subtract the new number by the original number
645 - 936 = -291
-291 ÷ 936 = -0.3108974358974359
-0.3108974358974359 x 100 = -31.09%