-97.85% is the change from 977 to 21
Calculation steps:
[( 21 - 977 ) ÷ 977] x 100 = -97.85%
Formula
Percentage change = [(21 - 977) / 977] x 100
Subtract the new number by the original number
21 - 977 = -956
-956 ÷ 977 = -0.9785056294779939
-0.9785056294779939 x 100 = -97.85%