-46.47% is the change from 170 to 91
Calculation steps:
[( 91 - 170 ) ÷ 170] x 100 = -46.47%
Formula
Percentage change = [(91 - 170) / 170] x 100
Subtract the new number by the original number
91 - 170 = -79
-79 ÷ 170 = -0.4647058823529412
-0.4647058823529412 x 100 = -46.47%