-20.2% is the change from 802 to 640
Calculation steps:
[( 640 - 802 ) ÷ 802] x 100 = -20.2%
Formula
Percentage change = [(640 - 802) / 802] x 100
Subtract the new number by the original number
640 - 802 = -162
-162 ÷ 802 = -0.20199501246882792
-0.20199501246882792 x 100 = -20.2%