-79.01% is the change from 81 to 17
Calculation steps:
[( 17 - 81 ) ÷ 81] x 100 = -79.01%
Formula
Percentage change = [(17 - 81) / 81] x 100
Subtract the new number by the original number
17 - 81 = -64
-64 ÷ 81 = -0.7901234567901234
-0.7901234567901234 x 100 = -79.01%