-37.5% is the change from 824 to 515
Calculation steps:
[( 515 - 824 ) ÷ 824] x 100 = -37.5%
Formula
Percentage change = [(515 - 824) / 824] x 100
Subtract the new number by the original number
515 - 824 = -309
-309 ÷ 824 = -0.375
-0.375 x 100 = -37.5%