-21.5% is the change from 842 to 661
Calculation steps:
[( 661 - 842 ) ÷ 842] x 100 = -21.5%
Formula
Percentage change = [(661 - 842) / 842] x 100
Subtract the new number by the original number
661 - 842 = -181
-181 ÷ 842 = -0.21496437054631828
-0.21496437054631828 x 100 = -21.5%