-77.5% is the change from 831 to 187
Calculation steps:
[( 187 - 831 ) ÷ 831] x 100 = -77.5%
Formula
Percentage change = [(187 - 831) / 831] x 100
Subtract the new number by the original number
187 - 831 = -644
-644 ÷ 831 = -0.7749699157641395
-0.7749699157641395 x 100 = -77.5%