-21.1% is the change from 635 to 501
Calculation steps:
[( 501 - 635 ) ÷ 635] x 100 = -21.1%
Formula
Percentage change = [(501 - 635) / 635] x 100
Subtract the new number by the original number
501 - 635 = -134
-134 ÷ 635 = -0.2110236220472441
-0.2110236220472441 x 100 = -21.1%