-86.6% is the change from 97 to 13
Calculation steps:
[( 13 - 97 ) ÷ 97] x 100 = -86.6%
Formula
Percentage change = [(13 - 97) / 97] x 100
Subtract the new number by the original number
13 - 97 = -84
-84 ÷ 97 = -0.865979381443299
-0.865979381443299 x 100 = -86.6%