-66.87% is the change from 501 to 166
Calculation steps:
[( 166 - 501 ) ÷ 501] x 100 = -66.87%
Formula
Percentage change = [(166 - 501) / 501] x 100
Subtract the new number by the original number
166 - 501 = -335
-335 ÷ 501 = -0.6686626746506986
-0.6686626746506986 x 100 = -66.87%