With 2009 new-vehicle sales representing about 60% of what they were in 2005, up to 40% fewer used cars were being traded in. Those declines have meant there are a lot fewer of the prime, low-mileage, late-model used cars around to sell in dealer lots. In particular, with gasoline prices higher this year, there aren’t a lot of late-model small used cars such as the Honda Civic, Toyota Corolla and Ford Focus available, and demand for them is up.