-30.13% is the change from 916 to 640
Calculation steps:
[( 640 - 916 ) ÷ 916] x 100 = -30.13%
Formula
Percentage change = [(640 - 916) / 916] x 100
Subtract the new number by the original number
640 - 916 = -276
-276 ÷ 916 = -0.30131004366812225
-0.30131004366812225 x 100 = -30.13%