-67.51% is the change from 511 to 166
Calculation steps:
[( 166 - 511 ) ÷ 511] x 100 = -67.51%
Formula
Percentage change = [(166 - 511) / 511] x 100
Subtract the new number by the original number
166 - 511 = -345
-345 ÷ 511 = -0.675146771037182
-0.675146771037182 x 100 = -67.51%