-47.1% is the change from 639 to 338
Calculation steps:
[( 338 - 639 ) ÷ 639] x 100 = -47.1%
Formula
Percentage change = [(338 - 639) / 639] x 100
Subtract the new number by the original number
338 - 639 = -301
-301 ÷ 639 = -0.47104851330203446
-0.47104851330203446 x 100 = -47.1%