-97.8% is the change from 956 to 21
Calculation steps:
[( 21 - 956 ) ÷ 956] x 100 = -97.8%
Formula
Percentage change = [(21 - 956) / 956] x 100
Subtract the new number by the original number
21 - 956 = -935
-935 ÷ 956 = -0.9780334728033473
-0.9780334728033473 x 100 = -97.8%