-29.39% is the change from 905 to 639
Calculation steps:
[( 639 - 905 ) ÷ 905] x 100 = -29.39%
Formula
Percentage change = [(639 - 905) / 905] x 100
Subtract the new number by the original number
639 - 905 = -266
-266 ÷ 905 = -0.29392265193370165
-0.29392265193370165 x 100 = -29.39%