-97.49% is the change from 837 to 21
Calculation steps:
[( 21 - 837 ) ÷ 837] x 100 = -97.49%
Formula
Percentage change = [(21 - 837) / 837] x 100
Subtract the new number by the original number
21 - 837 = -816
-816 ÷ 837 = -0.974910394265233
-0.974910394265233 x 100 = -97.49%