-72.73% is the change from 77 to 21
Calculation steps:
[( 21 - 77 ) ÷ 77] x 100 = -72.73%
Formula
Percentage change = [(21 - 77) / 77] x 100
Subtract the new number by the original number
21 - 77 = -56
-56 ÷ 77 = -0.7272727272727273
-0.7272727272727273 x 100 = -72.73%