-19.31% is the change from 642 to 518
Calculation steps:
[( 518 - 642 ) ÷ 642] x 100 = -19.31%
Formula
Percentage change = [(518 - 642) / 642] x 100
Subtract the new number by the original number
518 - 642 = -124
-124 ÷ 642 = -0.19314641744548286
-0.19314641744548286 x 100 = -19.31%