SANTA MONICA, Calif. -

In light of how gas prices climbed during the first half of the year, pushing up demand for compact cars, Edmunds.com calculated how much more dealers had to charge for these units in July versus January.

The site’s data revealed buyers paid about 10 percent more for three-year-old  used compact cars in July than in January.

By comparison, Edmunds noted prices for this segment rose just 1.6 percent over the same period in 2010 and 1.1 percent in 2008 — the last time price at the pump crept above $4 per gallon.

At the other end of the spectrum, site analysts discovered  that three-year-old large traditional SUVs saw a small drop in price (down 3.2 percent on average) from January to July.

However, Edmunds acknowledged this segment demonstrated much more stability than it did in 2008. That’s when the price of three-year-old large traditional SUVs plummeted 23 percent during the first seven months of the year.

“In 2008, consumers reacted to rising gas prices by running away from SUVs. In 2011, they reacted by running toward small cars,” explained Richard Arca, used-car analyst at Edmunds.

“This year’s pricing trends are also affected by the March earthquake in Japan, which for some time made it very difficult to find, for example, a new Toyota Prius or Honda Civic," he added. "That created a very aggressive market for similar used models.”

Based on Edmunds’ data, the price of a new 2010 Toyota Prius bought in July 2010 depreciated just 4.3 percent after one year, while the price of a new 2010 Honda Civic depreciated 5 percent over the same period.

By comparison, the site calculated the average price for all new 2010 models depreciated 28.9 percent during that time.

Overall, Edmunds indicated that used-vehicle prices have climbed 4.3 percent from January to July of this year. A year ago, the site said prices rose 3.0 percent over the same period.