-29.97% is the change from 921 to 645
Calculation steps:
[( 645 - 921 ) ÷ 921] x 100 = -29.97%
Formula
Percentage change = [(645 - 921) / 921] x 100
Subtract the new number by the original number
645 - 921 = -276
-276 ÷ 921 = -0.2996742671009772
-0.2996742671009772 x 100 = -29.97%