100% is the change from 170 to 340
Calculation steps:
[( 340 - 170 ) ÷ 170] x 100 = 100%
Formula
Percentage change = [(340 - 170) / 170] x 100
Subtract the new number by the original number
340 - 170 = 170
170 ÷ 170 = 1
1 x 100 = 100%
Example