The used-car industry enjoyed its strongest October in four years last month, as both franchised and independent dealers — in addition to private-party sales — climbed double-digit percentages, according to CNW Research.

Overall, there were 2.91 million used sales last month, up 12.4 percent year-over-year, CNW noted, with franchised dealers up a little more than 13 percent, while independents and casual sales both increased more than 11.5 percent.

The last time used sales were this high in October was 2007, when they reached 2.98 million vehicles.

Looking at some year-to-date data through October of this year, there have been 33.06 million used sales so far in 2011, compared to 31.58 million at this point in 2010.

Breaking last month’s results down further, CNW noted that franchised dealers sold 1.01 million used vehicles, up from 891,773 used sales in October 2010. Independents moved 979,583 used units, compared to 877,081 used sales a year ago.

There were 920,218 private-party sales, versus 824,772 sales last October.

The industry’s used sales were down from the 3.23 million in September, but this sequential decline is typical for October, according to CNW.