-34.23% is the change from 815 to 536
Calculation steps:
[( 536 - 815 ) ÷ 815] x 100 = -34.23%
Formula
Percentage change = [(536 - 815) / 815] x 100
Subtract the new number by the original number
536 - 815 = -279
-279 ÷ 815 = -0.3423312883435583
-0.3423312883435583 x 100 = -34.23%