-29.64% is the change from 921 to 648
Calculation steps:
[( 648 - 921 ) ÷ 921] x 100 = -29.64%
Formula
Percentage change = [(648 - 921) / 921] x 100
Subtract the new number by the original number
648 - 921 = -273
-273 ÷ 921 = -0.2964169381107492
-0.2964169381107492 x 100 = -29.64%