109.97% is the change from 391 to 821
Calculation steps:
[( 821 - 391 ) ÷ 391] x 100 = 109.97%
Formula
Percentage change = [(821 - 391) / 391] x 100
Subtract the new number by the original number
821 - 391 = 430
430 ÷ 391 = 1.0997442455242967
1.0997442455242967 x 100 = 109.97%