54.93% is the change from 639 to 990
Calculation steps:
[( 990 - 639 ) ÷ 639] x 100 = 54.93%
Formula
Percentage change = [(990 - 639) / 639] x 100
Subtract the new number by the original number
990 - 639 = 351
351 ÷ 639 = 0.5492957746478874
0.5492957746478874 x 100 = 54.93%