87.94% is the change from 340 to 639
Calculation steps:
[( 639 - 340 ) ÷ 340] x 100 = 87.94%
Formula
Percentage change = [(639 - 340) / 340] x 100
Subtract the new number by the original number
639 - 340 = 299
299 ÷ 340 = 0.8794117647058823
0.8794117647058823 x 100 = 87.94%