-89.5% is the change from 200 to 21
Calculation steps:
[( 21 - 200 ) ÷ 200] x 100 = -89.5%
Formula
Percentage change = [(21 - 200) / 200] x 100
Subtract the new number by the original number
21 - 200 = -179
-179 ÷ 200 = -0.895
-0.895 x 100 = -89.5%
Example