99.76% is the change from 420 to 839
Calculation steps:
[( 839 - 420 ) ÷ 420] x 100 = 99.76%
Formula
Percentage change = [(839 - 420) / 420] x 100
Subtract the new number by the original number
839 - 420 = 419
419 ÷ 420 = 0.9976190476190476
0.9976190476190476 x 100 = 99.76%