-87.26% is the change from 636 to 81
Calculation steps:
[( 81 - 636 ) ÷ 636] x 100 = -87.26%
Formula
Percentage change = [(81 - 636) / 636] x 100
Subtract the new number by the original number
81 - 636 = -555
-555 ÷ 636 = -0.8726415094339622
-0.8726415094339622 x 100 = -87.26%