-34.16% is the change from 972 to 640
Calculation steps:
[( 640 - 972 ) ÷ 972] x 100 = -34.16%
Formula
Percentage change = [(640 - 972) / 972] x 100
Subtract the new number by the original number
640 - 972 = -332
-332 ÷ 972 = -0.34156378600823045
-0.34156378600823045 x 100 = -34.16%