55.09% is the change from 639 to 991
Calculation steps:
[( 991 - 639 ) ÷ 639] x 100 = 55.09%
Formula
Percentage change = [(991 - 639) / 639] x 100
Subtract the new number by the original number
991 - 639 = 352
352 ÷ 639 = 0.5508607198748043
0.5508607198748043 x 100 = 55.09%