NADA Used Car Guide’s seasonally adjusted used-vehicle price index fell by 1 percent in September, bringing it to its lowest level since March 2011, according to its latest Guidelines report. 

Here’s what happened last month: Wholesale prices of vehicles up to 8 years old fell by 3.6 percent. While in line with predictions, it was the largest monthly decline thus far in 2016.

Price movement was led by small cars. Subcompact and compact car prices fell by 4 percent each — similar to the previous combined three-year average of 4.3 percent for the period. And large cars saw a loss of 3.7 percent, also in line with the segment’s prior three-year average.

Other mainstream segments fared better than average. Midsize car and utility losses were 3.5 percent and 3.4 percent, respectively. Losses for these segments during the previous three Septembers averaged 3.7 percent and 3.1 percent.

Compact and large utilities saw smaller monthly losses, at 3.2 percent and 3 percent, respectively. While lower than the industry average, these losses were higher than the prior three-year average for the segments.

Pickup truck price losses were notably light in September. Midsize pickup price losses were 1.6 percent, while large pickup prices fell by 1.3 percent. Over the previous three years, losses for both of those segments averaged 2.1 percent, which NADA Used Car Guide pointed out was low when looking at the big market picture.

Losses for luxury segments were mixed, but were all within a half point of the industry average. That being said, losses here were higher than the previous three Septembers.

Looking at things from a year-to-date perspective, the used-vehicle price index sits 3.6 percent below last year’s nine-month average. Used vehicle prices were 14.9 percent lower through September relative to all of 2015.

Depreciation among mainstream segments this year has been led by subcompact cars, whose prices have fallen by an average of 23.2 percent year to date.

And while truck and utility depreciation is rising, it’s still milder compared to cars. Midsize pickup prices were down by 7.8 percent through September, while large pickup and large utility prices fell by 7.7 percent and 7.1 percent, respectively.

Losses in luxury segments ranged from 14.2 percent to 17.9 percent. Large utilities were the only segment to perform better relative to 2015. Prices fell by 7.1 percent through September, compared to 8.7 percent during the same period last year.

NADA Used Car Guide predicts that prices of vehicles up to 8 years old will fall by 3.2 percent to 3.7 percent in October relative to September. This is more than the 2.7 percent decline averaged for the month in 2015.

Looking ahead, monthly losses are expected to be softer for the rest of the year. As a result, NADA Used Car Guide’s full-year forecast has prices down by an average of 4 percent on an index basis from 2015.