-18.92% is the change from 518 to 420
Calculation steps:
[( 420 - 518 ) ÷ 518] x 100 = -18.92%
Formula
Percentage change = [(420 - 518) / 518] x 100
Subtract the new number by the original number
420 - 518 = -98
-98 ÷ 518 = -0.1891891891891892
-0.1891891891891892 x 100 = -18.92%