-97.7% is the change from 913 to 21
Calculation steps:
[( 21 - 913 ) ÷ 913] x 100 = -97.7%
Formula
Percentage change = [(21 - 913) / 913] x 100
Subtract the new number by the original number
21 - 913 = -892
-892 ÷ 913 = -0.976998904709748
-0.976998904709748 x 100 = -97.7%