NEW YORK (CNN/Money) - Motorcycle sales jumped to their highest level in 25 years in 2004, according to a published report.

The Motorcycle Industry Council reported that an increase in female riders and the rise in popularity of motor scooters and other small two-wheelers pushed sales up nearly 5 percent for the year.

The sales total topped one million for the second straight year, according to the Council. But sales could slow if prices rise due to increased costs for steel and other raw materials, as well as a weaker dollar, which could raise the price of imported motorcycles that account for a majority of U.S. sales.

Harley Davidson (Research) is the only U.S.-based manufacturer among the top five makers in terms of market share with just under a quarter of the market in 2003, the most recent year for which share was available.

Harley Davidson reported record fourth-quarter and full-year revenue and earnings early Thursday, as it topped $5 billion in sales for the first time. The company beat the consensus analyst forecast from earnings tracker First Call, and said it expects growth to continue in 2005.

Shares of Harley Davidson gained nearly 28 percent in 2004, although shares have retreated about 2 percent so far this month ahead of Thursday's report.

Prices on motorcycles range from $1,800 for a low-powered scooter to more than $20,000 for a fully-equipped road bike, according to Mike Mount, a spokesperson from the Motorcycle Industry Council. The smaller off-road bikes are an important driver in the growth of the sector, attracting more families to buy.

The Council reported that the average age of motorcycle owners has been rising, reaching 41 in 2003, the latest year for which information is available. In 1998 the average age stood at 38. Most riders were married but the percentage of single riders has been climbing.