Mercedes-Benz USA (MBUSA) has reported March sales of 15,602 vehicles, a decline of 25 percent. The volume leaders for the month were the C, E, and GLK-Class with sales of 5,008, 1,978, and 2,598 units, respectively. On a year-to-date basis, the company has sold 40,234 new vehicles, a decrease of 30.2 percent over the comparable period last year. Separately, through the Mercedes-Benz Certified Pre-Owned (MBCPO) program, MBUSA sold 6,614 vehicles in March; a 29.4 percent increase compared to March 2008 sales of 5,110 vehicles. Year-to-date sales for the MBCPO program are 19,162, a 44.6 percent increase over 2008 year-to-date sales (13,252 vehicles) during the same timeframe. As for how Mercedes-Benz USA's competitors fared for the month, here's a quick rundown: