-85.94% is the change from 647 to 91
Calculation steps:
[( 91 - 647 ) ÷ 647] x 100 = -85.94%
Formula
Percentage change = [(91 - 647) / 647] x 100
Subtract the new number by the original number
91 - 647 = -556
-556 ÷ 647 = -0.8593508500772797
-0.8593508500772797 x 100 = -85.94%