We will have the following:
First, we find the difference:
[tex]68-53=15[/tex]Now, we calculate what percentage represents 15 if 53 is the 100%, that is:
[tex]x=\frac{15\cdot100}{53}\Rightarrow x=\frac{1500}{53}\Rightarrow x\approx28.3[/tex]So, the change was of exactly 1500/53 %, that is approximately 28.3%.