-15.96% is the change from 639 to 537
Calculation steps:
[( 537 - 639 ) ÷ 639] x 100 = -15.96%
Formula
Percentage change = [(537 - 639) / 639] x 100
Subtract the new number by the original number
537 - 639 = -102
-102 ÷ 639 = -0.1596244131455399
-0.1596244131455399 x 100 = -15.96%