-58.82% is the change from 51 to 21
Calculation steps:
[( 21 - 51 ) ÷ 51] x 100 = -58.82%
Formula
Percentage change = [(21 - 51) / 51] x 100
Subtract the new number by the original number
21 - 51 = -30
-30 ÷ 51 = -0.5882352941176471
-0.5882352941176471 x 100 = -58.82%