-91.79% is the change from 621 to 51
Calculation steps:
[( 51 - 621 ) ÷ 621] x 100 = -91.79%
Formula
Percentage change = [(51 - 621) / 621] x 100
Subtract the new number by the original number
51 - 621 = -570
-570 ÷ 621 = -0.9178743961352657
-0.9178743961352657 x 100 = -91.79%