213.86% is the change from 166 to 521
Calculation steps:
[( 521 - 166 ) ÷ 166] x 100 = 213.86%
Formula
Percentage change = [(521 - 166) / 166] x 100
Subtract the new number by the original number
521 - 166 = 355
355 ÷ 166 = 2.13855421686747
2.13855421686747 x 100 = 213.86%