-2.6% is the change from 770 to 750
Calculation steps:
[( 750 - 770 ) ÷ 770] x 100 = -2.6%
Formula
Percentage change = [(750 - 770) / 770] x 100
Subtract the new number by the original number
750 - 770 = -20
-20 ÷ 770 = -0.025974025974025976
-0.025974025974025976 x 100 = -2.6%