Do you and your dad not drive much, or do I drive a lot? I bought my car new about a year and a half old. So far, it has around 32,000 miles on it.
My dad puts on his car around 15-20k a year. My car on the other hand for the first 3 years I was only doing like 9k a year on it. Next year I did something like 20k and then 15k. Now it is dropped back off.
Those high years line up with me having a job. After I got laid off the amount of driving dropped a lot more.
As to figure out how much you drive the average car gets between 12-15k miles on it per year. 15k being the high side.