-5.54% is the change from 921 to 870
Calculation steps:
[( 870 - 921 ) ÷ 921] x 100 = -5.54%
Formula
Percentage change = [(870 - 921) / 921] x 100
Subtract the new number by the original number
870 - 921 = -51
-51 ÷ 921 = -0.05537459283387622
-0.05537459283387622 x 100 = -5.54%