-0.61% is the change from 815 to 810
Calculation steps:
[( 810 - 815 ) ÷ 815] x 100 = -0.61%
Formula
Percentage change = [(810 - 815) / 815] x 100
Subtract the new number by the original number
810 - 815 = -5
-5 ÷ 815 = -0.006134969325153374
-0.006134969325153374 x 100 = -0.61%