-2% is the change from 950 to 931
Calculation steps:
[( 931 - 950 ) ÷ 950] x 100 = -2%
Formula
Percentage change = [(931 - 950) / 950] x 100
Subtract the new number by the original number
931 - 950 = -19
-19 ÷ 950 = -0.02
-0.02 x 100 = -2%
Example