Through eight months of the year, there have been 3.12 million auction sales of cars up to 8 years in age, according to NADA Used Car Guide, which said this represents a 7-percent increase over the same period of 2015.

The increase in late-model auction sales (cars up to 3 years old) has been sharper: There have been 1.82 million sales, a 10-percent increase, the company said in its latest Guidelines report.

Leading the late-model crowd once again are midsize cars, with 349,000 units sold through August, and compact cars (281,000).  

NADA Used Car Guide points out, however, that compact utilities, midsize utilities and large pickups are showing some nice gains.

In fact, those three lead late-model growth, with year-to-date increases of 34 percent (large pickups), 32 percent (compact utilities) and 30 percent (midsize utilities).

Auction volume for luxury compact utilities is also up 30 percent.