-32.74% is the change from 950 to 639
Calculation steps:
[( 639 - 950 ) ÷ 950] x 100 = -32.74%
Formula
Percentage change = [(639 - 950) / 950] x 100
Subtract the new number by the original number
639 - 950 = -311
-311 ÷ 950 = -0.3273684210526316
-0.3273684210526316 x 100 = -32.74%