-90.4% is the change from 531 to 51
Calculation steps:
[( 51 - 531 ) ÷ 531] x 100 = -90.4%
Formula
Percentage change = [(51 - 531) / 531] x 100
Subtract the new number by the original number
51 - 531 = -480
-480 ÷ 531 = -0.903954802259887
-0.903954802259887 x 100 = -90.4%