The average price for used cars saw its largest drop in nearly a year the National Automobile Dealers Association (NADA) reported this week.

The price of used cars and light trucks up to eight model years in age fell an average of 2.6 percent in September, marking the highest rate of decline recorded since the 2.9 percent drop in October of last year, according to an NADA press release. The drop in price was likely due to the time of year, as well as, larger quantities of one-year-old units entering the used market.

"Historically, the rate of used vehicle depreciation begins to accelerate in September as consumer attention shifts toward more pressing seasonal obligations and because larger quantities of one-year-old units entering the used market converge," Jonathan Banks, executive automotive analyst for the NADA Used Car Guide, said in the press release.

The number of 2013 model year units sold at auction last month, most of which came from rental companies, grew by more than 24 percent compared to August.

Compact car, midsize car and midsize van segments, which have experienced the highest price increases in the 2013 model year supply, fell by a combined average of 2.9, the biggest price decline in September, according to the press release. Luxury car prices, weighed down by rising off-lease volume, fell by a similar figure of 2.8 percent.

Prices for most utility cars, including compact, midsize and luxury, all fell within a tight range of 1.9 percent to 2.2 percent in September, while prices for large SUVs and pickups continued to show strength as favorable fuel prices and a tight supply held declines to 0.6 percent and 1 percent, respectively.

The average price of used vehicles up to eight model years in age was $15,011 this year, up 0.5 percent from 2012's average of $14,990.

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