-64.69% is the change from 640 to 226
Calculation steps:
[( 226 - 640 ) ÷ 640] x 100 = -64.69%
Formula
Percentage change = [(226 - 640) / 640] x 100
Subtract the new number by the original number
226 - 640 = -414
-414 ÷ 640 = -0.646875
-0.646875 x 100 = -64.69%