Ess is going to purchase a new car that has a list price of $29,190. She is planning on trading in her good-condition 2006 Dodge Dakota and financing the rest of the cost over four years, paying monthly. Her finance plan has an interest rate of 10.73%, compounded monthly. Tess will also be responsible for 7.14% sales tax, a $1,235 vehicle registration fee, and a $97 documentation fee. If the dealer gives Tess 75% of the listed trade-in price on her car, once the financing is paid off, what percent of the total amount paid over four years would be interest? (Consider the trade-in to be a reduction in the amount paid.)