BMW of North America, Inc. continued its winning sales streak in May, reporting sales of 15,323 vehicles, compared to 13,594 for the same period a year ago, an increase of 13 percent. Year-to-date sales increased 15.4 percent to 73,449 compared to 63,627 in 1999. Sales of BMW automobiles increased to 13,710 for May, making it the 20th consecutive month the company has broken the previous year's car sales performance. The 7 Series enjoyed a particularly strong sales gain - up 18 percent versus the previous month and 10 percent year-to-date. Year-to-date automobile sales increased 6 percent, to 67,510 compared to 63,627 in 1999.