-20.5% is the change from 644 to 512
Calculation steps:
[( 512 - 644 ) ÷ 644] x 100 = -20.5%
Formula
Percentage change = [(512 - 644) / 644] x 100
Subtract the new number by the original number
512 - 644 = -132
-132 ÷ 644 = -0.20496894409937888
-0.20496894409937888 x 100 = -20.5%