206.63% is the change from 166 to 509
Calculation steps:
[( 509 - 166 ) ÷ 166] x 100 = 206.63%
Formula
Percentage change = [(509 - 166) / 166] x 100
Subtract the new number by the original number
509 - 166 = 343
343 ÷ 166 = 2.066265060240964
2.066265060240964 x 100 = 206.63%