-67.97% is the change from 640 to 205
Calculation steps:
[( 205 - 640 ) ÷ 640] x 100 = -67.97%
Formula
Percentage change = [(205 - 640) / 640] x 100
Subtract the new number by the original number
205 - 640 = -435
-435 ÷ 640 = -0.6796875
-0.6796875 x 100 = -67.97%