-85.71% is the change from 637 to 91
Calculation steps:
[( 91 - 637 ) ÷ 637] x 100 = -85.71%
Formula
Percentage change = [(91 - 637) / 637] x 100
Subtract the new number by the original number
91 - 637 = -546
-546 ÷ 637 = -0.8571428571428571
-0.8571428571428571 x 100 = -85.71%