-72.31% is the change from 921 to 255
Calculation steps:
[( 255 - 921 ) ÷ 921] x 100 = -72.31%
Formula
Percentage change = [(255 - 921) / 921] x 100
Subtract the new number by the original number
255 - 921 = -666
-666 ÷ 921 = -0.7231270358306189
-0.7231270358306189 x 100 = -72.31%