-3.46% is the change from 520 to 502
Calculation steps:
[( 502 - 520 ) ÷ 520] x 100 = -3.46%
Formula
Percentage change = [(502 - 520) / 520] x 100
Subtract the new number by the original number
502 - 520 = -18
-18 ÷ 520 = -0.03461538461538462
-0.03461538461538462 x 100 = -3.46%