-32.7% is the change from 951 to 640
Calculation steps:
[( 640 - 951 ) ÷ 951] x 100 = -32.7%
Formula
Percentage change = [(640 - 951) / 951] x 100
Subtract the new number by the original number
640 - 951 = -311
-311 ÷ 951 = -0.3270241850683491
-0.3270241850683491 x 100 = -32.7%