-15.31% is the change from 921 to 780
Calculation steps:
[( 780 - 921 ) ÷ 921] x 100 = -15.31%
Formula
Percentage change = [(780 - 921) / 921] x 100
Subtract the new number by the original number
780 - 921 = -141
-141 ÷ 921 = -0.15309446254071662
-0.15309446254071662 x 100 = -15.31%