-18.18% is the change from 209 to 171
Calculation steps:
[( 171 - 209 ) ÷ 209] x 100 = -18.18%
Formula
Percentage change = [(171 - 209) / 209] x 100
Subtract the new number by the original number
171 - 209 = -38
-38 ÷ 209 = -0.18181818181818182
-0.18181818181818182 x 100 = -18.18%