-16.5% is the change from 824 to 688
Calculation steps:
[( 688 - 824 ) ÷ 824] x 100 = -16.5%
Formula
Percentage change = [(688 - 824) / 824] x 100
Subtract the new number by the original number
688 - 824 = -136
-136 ÷ 824 = -0.1650485436893204
-0.1650485436893204 x 100 = -16.5%