-4.38% is the change from 639 to 611
Calculation steps:
[( 611 - 639 ) ÷ 639] x 100 = -4.38%
Formula
Percentage change = [(611 - 639) / 639] x 100
Subtract the new number by the original number
611 - 639 = -28
-28 ÷ 639 = -0.04381846635367762
-0.04381846635367762 x 100 = -4.38%