28.7% is the change from 770 to 991
Calculation steps:
[( 991 - 770 ) ÷ 770] x 100 = 28.7%
Formula
Percentage change = [(991 - 770) / 770] x 100
Subtract the new number by the original number
991 - 770 = 221
221 ÷ 770 = 0.287012987012987
0.287012987012987 x 100 = 28.7%