-72.34% is the change from 640 to 177
Calculation steps:
[( 177 - 640 ) ÷ 640] x 100 = -72.34%
Formula
Percentage change = [(177 - 640) / 640] x 100
Subtract the new number by the original number
177 - 640 = -463
-463 ÷ 640 = -0.7234375
-0.7234375 x 100 = -72.34%