The average fuel economy of 2012 model year vehicles is 14 percent higher than the same mark of just four years earlier, according to a University of Michigan study, confirming automakers' push to appeal to consumers' desires for more fuel efficient vehicles.

Model-year 2012 light-duty vehicles -- cars, pickup trucks, minivans, vans and sport utility vehicles -- averaged 21.5 miles per gallon, which compares to 18.9 miles per gallon for model-year 2008 vehicles. The number is also up from 21.2 from last year, 20.7 two years ago and 19 in 2009, continuing a steady trend.

This implies that consumers tend to choose vehicle models with better fuel economy than the average of all vehicles available, said Brandon Schoettle of the University of Michigan Transportation Research Institute. The recent economic downturn, coupled with rising gas prices, has led to an increased interest in purchasing more fuel-efficient vehicles.

And that fuel efficiency bumps up to an average of about one or two miles per gallon for vehicles sold. In 2011, vehicles sold averaged 22.5 miles per gallon, compared with the 21.2 average for all vehicles on the market.

The report comes as gas prices are prepared to heat up into the spring and summer seasons in the U.S. The national average Monday stood at $3.51, the earliest in the year that gas prices have reached that level. Typically, January and February see prices fall before rising in the spring and summer seasons.

Gas prices are already jumping this year because of tensions in Greece and in Iran. Oil prices rose Monday as the Greek government approved austerity measures to save the country from default.

In 2011, the administration of President Barack Obama outlined new fuel economy standards, which require automakers to meet an average of 54.5 miles per gallon by 2025 for cars and light trucks. That's more than double the current average, according to the study.

The University of Michigan study follows a study conducted by Deloitte in January, which suggested that Generation Y consumers -- those between the ages of 19 and 31 -- prefer vehicles with some electrified elements.

At the 2012 North American International Auto Show last month in Detroit, Nissan North America Vice President Al Castignetti helped introduce a concept electric van called the eNV200. He also marveled at the prevalence of electric vehicle offerings across the showroom.

What I find ironic is that if you walk around this show today, every manufacturer in this show has an EV offering, whether it be concept or production, Castignetti said in an interview. But three years ago, everybody was telling us we couldn't do it, and now everybody's got one in their spots.