The latest Used Car Market Report from Edmunds.com indicates that lease penetration in 2014 reached 27 percent, just five years after rates fell below 17 percent.

One of the segments of the car business that has been a big beneficiary of the rampant bounce-back in leasing has been the certified pre-owned business.

“New-vehicle leasing continues to grow, and the lease returns have helped supply used car inventory — particularly CPO vehicles,” Edmunds’ analysts said in the report. “Additionally, leasing has become so prevalent in every vehicle segment and that has helped to bolster used inventories for segments that have traditionally been purchase-heavy.”

The pool of CPO-worthy cars continues to climb, leading to a record year for both CPO sales volume and market share of franchised used sales in 2014, the report indicates.

“That (record-setting) is expected to continue in 2015 with trade-ins and lease returns expected to increase,” Edmunds analysts pointed out.

So it’s not just robust leasing that lifting the certified market; trade-ins are helping, too.

There were 6.2 million new-car sales with a trade-in during 2014, according to Edmunds’ report. That’s up from a recent low point of 3.6 million in 2009. Each of the past five years has represented a steady increase in the number of new sales with trade-ins, the Edmunds data shows.

“The sourcing of used inventory from new car sales with a trade-in continues to grow after being severely affected by the economic downturn. Since 2012, new cars sales with a trade-in have been 5 million-plus (each year), which has helped expand the depressed used car population,” Edmunds noted.