-94.38% is the change from 640 to 36
Calculation steps:
[( 36 - 640 ) ÷ 640] x 100 = -94.38%
Formula
Percentage change = [(36 - 640) / 640] x 100
Subtract the new number by the original number
36 - 640 = -604
-604 ÷ 640 = -0.94375
-0.94375 x 100 = -94.38%