33.13% is the change from 166 to 221
Calculation steps:
[( 221 - 166 ) ÷ 166] x 100 = 33.13%
Formula
Percentage change = [(221 - 166) / 166] x 100
Subtract the new number by the original number
221 - 166 = 55
55 ÷ 166 = 0.3313253012048193
0.3313253012048193 x 100 = 33.13%