-20.87% is the change from 647 to 512
Calculation steps:
[( 512 - 647 ) ÷ 647] x 100 = -20.87%
Formula
Percentage change = [(512 - 647) / 647] x 100
Subtract the new number by the original number
512 - 647 = -135
-135 ÷ 647 = -0.20865533230293662
-0.20865533230293662 x 100 = -20.87%