Although new-vehicle retail sales in July are projected to decrease 19 percent from July 2008, this marks an improvement in year-over-year declines observed for the first half of 2009, according to J.D. Power and Associates, which gathers real-time transaction data from more than 10,000 dealerships across the United States. Sales for the first half of 2009 are down 32 percent from the same period in 2008.