-37.09% is the change from 639 to 402
Calculation steps:
[( 402 - 639 ) ÷ 639] x 100 = -37.09%
Formula
Percentage change = [(402 - 639) / 639] x 100
Subtract the new number by the original number
402 - 639 = -237
-237 ÷ 639 = -0.37089201877934275
-0.37089201877934275 x 100 = -37.09%