-4.06% is the change from 960 to 921
Calculation steps:
[( 921 - 960 ) ÷ 960] x 100 = -4.06%
Formula
Percentage change = [(921 - 960) / 960] x 100
Subtract the new number by the original number
921 - 960 = -39
-39 ÷ 960 = -0.040625
-0.040625 x 100 = -4.06%