WASHINGTON - U.S. automakers have surpassed imported brands for the first time in a survey that measures the quality of new cars and trucks.

J.D. Power and Associates said Thursday that owners of domestic cars reported fewer problems on average during the first 90 days of ownership than foreign cars and trucks.

It marks the first time that has happened in the 24 years the industry research group has conducted the annual quality study.

J.D. Power said Ford showed some of the biggest gains in quality among individual brands, moving into the fifth spot. Porsche was the top scorer. Toyota, which has suffered through huge safety recalls earlier this year, saw its score drop.

"Domestic automakers have made impressive strides in steadily improving vehicle quality," said David Sargent, J.D. Power's vice president of global research.

The study ranks vehicles according to the number of problems reported per 100 vehicles. The overall average for the industry was 109 problems per 100 vehicles. That industry average has fallen steadily over the past decade.

U.S. manufacturers scored an average of 108 problems, while imports posted 109 problems. That is a marked difference than just 10 years ago, when imported brands had far fewer initial problems than those made by U.S. companies.

Luxury brands topped the list of brands, with Acura and Mercedes-Benz holding the second and third spots. Daimler, which makes the Mercedes-Benz, had the best performing plant, an assembly facility in East London, South Africa.

Land Rover had the highest overall number of average problems with 170.

Ford was the best scorer among non-luxury brands, with 93 problems per 100 vehicles. J.D. Power said that Ford has shown steady improvement over the last nine years.

The rankings are closely watched by automakers, which frequently use them in advertising campaigns. Ford vice president of quality Bennie Fowler said in a statement that the survey shows Ford's "steady and meticulous attention to new model launches."

Toyota's ranking dropped to the 21st spot, down from the sixth ranking in 2009. The Japanese automaker has built a strong reputation for vehicle quality, but has seen its image suffer after wide reports of unintended acceleration in Toyota vehicles.

Here are the top three finishers in each segment:

Sub-compact Car Highest Ranked: Hyundai Accent

Toyota Yaris

Honda Fit

Compact Car Highest Ranked: Ford Focus

Honda Civic

Hyundai Elantra

Compact Sporty Car* Highest Ranked: Mazda MX-5 Miata

Scion tC

Compact Premium Sporty Car* Highest Ranked: Volvo C70

Mercedes-Benz E-Class Coupe

Entry Premium Car Highest Ranked: Mercedes-Benz C-Class

Acura TL

Cadillac CTS

Midsize Premium Car Highest Ranked: Lexus GS

Mercedes-Benz E-Class Sedan

Volvo S80

Midsize Sporty Car* Highest Ranked: Ford Mustang

Dodge Challenger

Large Premium Car Highest Ranked: Lexus LS 460

Mercedes-Benz S-Class

Porsche Panamera

Midsize Car Highest Ranked: Honda Accord

Ford Fusion

Chevrolet Malibu

Large Car Highest Ranked: Ford Taurus

Buick Lucerne

Nissan Maxima

*No other model in this segment performs above the segment average.