-86.72% is the change from 610 to 81
Calculation steps:
[( 81 - 610 ) ÷ 610] x 100 = -86.72%
Formula
Percentage change = [(81 - 610) / 610] x 100
Subtract the new number by the original number
81 - 610 = -529
-529 ÷ 610 = -0.8672131147540983
-0.8672131147540983 x 100 = -86.72%