-76.47% is the change from 170 to 40
Calculation steps:
[( 40 - 170 ) ÷ 170] x 100 = -76.47%
Formula
Percentage change = [(40 - 170) / 170] x 100
Subtract the new number by the original number
40 - 170 = -130
-130 ÷ 170 = -0.7647058823529411
-0.7647058823529411 x 100 = -76.47%