-30.84% is the change from 921 to 637
Calculation steps:
[( 637 - 921 ) ÷ 921] x 100 = -30.84%
Formula
Percentage change = [(637 - 921) / 921] x 100
Subtract the new number by the original number
637 - 921 = -284
-284 ÷ 921 = -0.30836047774158526
-0.30836047774158526 x 100 = -30.84%