-30.65% is the change from 920 to 638
Calculation steps:
[( 638 - 920 ) ÷ 920] x 100 = -30.65%
Formula
Percentage change = [(638 - 920) / 920] x 100
Subtract the new number by the original number
638 - 920 = -282
-282 ÷ 920 = -0.3065217391304348
-0.3065217391304348 x 100 = -30.65%