-81.8% is the change from 665 to 121
Calculation steps:
[( 121 - 665 ) ÷ 665] x 100 = -81.8%
Formula
Percentage change = [(121 - 665) / 665] x 100
Subtract the new number by the original number
121 - 665 = -544
-544 ÷ 665 = -0.8180451127819549
-0.8180451127819549 x 100 = -81.8%