21.21% is the change from 66 to 80
Calculation steps:
[( 80 - 66 ) ÷ 66] x 100 = 21.21%
Formula
Percentage change = [(80 - 66) / 66] x 100
Subtract the new number by the original number
80 - 66 = 14
14 ÷ 66 = 0.21212121212121213
0.21212121212121213 x 100 = 21.21%