The percentage increase is rounded to 34%.
To find he what the percentage of a number is using a fraction just divide the numerator by the denominator.
So 1/3 is 0.333333333 and 2/3 is .666666667. These answers are your percentage in decimal form is .33 would be 33 and .667 would be rounded to 67. The last step is just subtracting to find difference 67-33= 34.
I hope I helped!