-86.36% is the change from 667 to 91
Calculation steps:
[( 91 - 667 ) ÷ 667] x 100 = -86.36%
Formula
Percentage change = [(91 - 667) / 667] x 100
Subtract the new number by the original number
91 - 667 = -576
-576 ÷ 667 = -0.863568215892054
-0.863568215892054 x 100 = -86.36%