-60% is the change from 170 to 68
Calculation steps:
[( 68 - 170 ) ÷ 170] x 100 = -60%
Formula
Percentage change = [(68 - 170) / 170] x 100
Subtract the new number by the original number
68 - 170 = -102
-102 ÷ 170 = -0.6
-0.6 x 100 = -60%
Example