51.8% is the change from 639 to 970
Calculation steps:
[( 970 - 639 ) ÷ 639] x 100 = 51.8%
Formula
Percentage change = [(970 - 639) / 639] x 100
Subtract the new number by the original number
970 - 639 = 331
331 ÷ 639 = 0.5179968701095462
0.5179968701095462 x 100 = 51.8%