-30.12% is the change from 913 to 638
Calculation steps:
[( 638 - 913 ) ÷ 913] x 100 = -30.12%
Formula
Percentage change = [(638 - 913) / 913] x 100
Subtract the new number by the original number
638 - 913 = -275
-275 ÷ 913 = -0.30120481927710846
-0.30120481927710846 x 100 = -30.12%