-18.68% is the change from 637 to 518
Calculation steps:
[( 518 - 637 ) ÷ 637] x 100 = -18.68%
Formula
Percentage change = [(518 - 637) / 637] x 100
Subtract the new number by the original number
518 - 637 = -119
-119 ÷ 637 = -0.18681318681318682
-0.18681318681318682 x 100 = -18.68%