8.78% is the change from 911 to 991
Calculation steps:
[( 991 - 911 ) ÷ 911] x 100 = 8.78%
Formula
Percentage change = [(991 - 911) / 911] x 100
Subtract the new number by the original number
991 - 911 = 80
80 ÷ 911 = 0.08781558726673985
0.08781558726673985 x 100 = 8.78%