-1.09% is the change from 824 to 815
Calculation steps:
[( 815 - 824 ) ÷ 824] x 100 = -1.09%
Formula
Percentage change = [(815 - 824) / 824] x 100
Subtract the new number by the original number
815 - 824 = -9
-9 ÷ 824 = -0.010922330097087379
-0.010922330097087379 x 100 = -1.09%