The purchase of an average-priced new vehicle during the fourth quarter of 2004 took 20.6 weeks of median family income, before taxes, according to the Auto Affordability Index compiled by Detroit-based Comerica Bank. This is 0.2 weeks more affordable than third quarter's 20.8 weeks. Total cost, including financing charges, came to $28,127 in the fourth quarter, 1.8% up from third quarter 2004, and 2.0% above year-earlier levels. Median family income rose 2.6% from the third quarter and is up 6.4% from a year ago. Looking at some historical figures reveals that car prices are even more affordable than those of 1975.