-86% is the change from 643 to 90
Calculation steps:
[( 90 - 643 ) ÷ 643] x 100 = -86%
Formula
Percentage change = [(90 - 643) / 643] x 100
Subtract the new number by the original number
90 - 643 = -553
-553 ÷ 643 = -0.8600311041990669
-0.8600311041990669 x 100 = -86%