-91.97% is the change from 635 to 51
Calculation steps:
[( 51 - 635 ) ÷ 635] x 100 = -91.97%
Formula
Percentage change = [(51 - 635) / 635] x 100
Subtract the new number by the original number
51 - 635 = -584
-584 ÷ 635 = -0.9196850393700787
-0.9196850393700787 x 100 = -91.97%