-19.72% is the change from 639 to 513
Calculation steps:
[( 513 - 639 ) ÷ 639] x 100 = -19.72%
Formula
Percentage change = [(513 - 639) / 639] x 100
Subtract the new number by the original number
513 - 639 = -126
-126 ÷ 639 = -0.19718309859154928
-0.19718309859154928 x 100 = -19.72%