-66.26% is the change from 815 to 275
Calculation steps:
[( 275 - 815 ) ÷ 815] x 100 = -66.26%
Formula
Percentage change = [(275 - 815) / 815] x 100
Subtract the new number by the original number
275 - 815 = -540
-540 ÷ 815 = -0.6625766871165644
-0.6625766871165644 x 100 = -66.26%