-82.02% is the change from 506 to 91
Calculation steps:
[( 91 - 506 ) ÷ 506] x 100 = -82.02%
Formula
Percentage change = [(91 - 506) / 506] x 100
Subtract the new number by the original number
91 - 506 = -415
-415 ÷ 506 = -0.8201581027667985
-0.8201581027667985 x 100 = -82.02%