-80.95% is the change from 21 to 4
Calculation steps:
[( 4 - 21 ) ÷ 21] x 100 = -80.95%
Formula
Percentage change = [(4 - 21) / 21] x 100
Subtract the new number by the original number
4 - 21 = -17
-17 ÷ 21 = -0.8095238095238095
-0.8095238095238095 x 100 = -80.95%