The number of ’12 car nameplates subject to the U.S. gas-guzzler tax is up some 30% compared with prior-year, according to a WardsAuto analysis of Environmental Protection Agency data.

Fifty-two ’12 nameplates fail to meet the 22.5 mpg (10.4 L/100 km) fuel-economy threshold needed to escape the penalty, which can range from $1,000 to $7,000, depending on EPA ratings. Factor in all the variations of each and that number swells to 71.

That’s up from the 39 nameplates and 63 total variations tagged gas-guzzlers in the ’11-model year.

Luxury brands dominate the list, in terms of raw numbers. BMW has the most offerings subject to the tax at 13. But nine of those are variants of the brand’s flagship 7-Series.

BMW’s total is down from 16 in ’11, according to preliminary EPA fuel-economy data.

Mercedes and Audi are close behind with 10 each. Mercedes’ total is one more than its ’11 tally, while various configurations of the R8 and R8 Spyder account for eight of Audi’s gas guzzlers.

The exotics lead the way in terms of saturation. Every model offered by Aston Martin, Lamborghini, Bugatti, Maserati and Rolls Royce is subject to the tax. But none of these marques comprise more than a handful of models.

Roush, with its lone offering, the Stage 3 Mustang, is the only other brand to earn this distinction.

Of the U.S. market’s Big Six auto makers, three boast guzzler-free lineups: Ford, Honda and Nissan.

Implemented in 1978 as part of the Energy Act, the gas-guzzler tax is levied against auto makers as a penalty for producing cars with exceptionally poor fuel economy. Light trucks are exempt.

emayne@wardsauto.com