WASHINGTON (CNN) - The Acura Integra tops a new study listing the most stolen passenger vehicles for the model years 1999-2001, according to the Highway Loss Data Institute.

The list correlates numbers of each 1999-2001 model passenger vehicle thought to be on the road with the frequency that it is stolen to determine which cars thieves want most often. Other studies don't use that formula -- usually concluding that the most stolen vehicles are models that most populate the highways, the institute said.

Theft investigators believe that Integras are so popular with thieves because of their parts, according to Kim Hazelbaker, HLDI senior vice president.

"Many of those parts, like the more powerful engine, end up on modified Honda Civics," Hazelbaker said. The Civic and the Integra share the same platform.

According to the study, the Integra was stolen with a frequency of 21.7 times per 1,000 insured vehicles on the road in a year.

The Integra was stolen more than eight times as often as the average car, and 2.5 times more frequently than the Jeep Wrangler -- the vehicle second on the list -- according to the institute.

The average U.S. car is stolen 2.6 times per 1,000 insured vehicles, according to the study. The Wrangler is stolen, the institute said, 8.5 times per 1,000 insured vehicles.