100% is the change from 278 to 556
Calculation steps:
[( 556 - 278 ) ÷ 278] x 100 = 100%
Formula
Percentage change = [(556 - 278) / 278] x 100
Subtract the new number by the original number
556 - 278 = 278
278 ÷ 278 = 1
1 x 100 = 100%
Example