SANTA MONICA, Calif. — Sales of certified pre-owned vehicles hit an all-time high of 2.3 million units sold in 2014, making up 20.8% of total used-car sales at franchised dealerships, according to the latest Used Vehicle Market Report from Edmunds.com.

Edmunds said it expects this trend to continue through 2015, with lease vehicles expected to return to dealerships at a faster rate than in previous years.

“This allows dealers to maintain a large CPO inventory," said Jessica Caldwell, senior analyst at Edmunds.com. “Car shoppers are finding a great selection to choose from, and in the current economy, many are comfortable spending a bit more for that extra peace of mind that a CPO car brings.”

Used cars that are lightly used are appealing to car shoppers because they are more often equipped with modern technology and have already taken the biggest hit in depreciation, added Caldwell. In 2014, 19% of used vehicles sold were one to two years old, up from 14% in 2013.

The average transaction price of a used car also increased from $15,900 in 2013 to $16,800 in 2014. One-year-old vehicles sold at an average of $30,000, increasing 5.7% over 2013. Edmunds attributed the increase to several factors, including low interest rates, longer loan repayment terms and declining gas prices. Customers also sought out larger, more expensive vehicles, bu they were able to pay less monthly for them, Edmunds noted.

The full Used Vehicle Market Report can be found in the Edmunds.com Industry Center.