The Edmunds.com price index for new vehicles increased slightly, from 98.6 in June to 98.7 in July. The average discount from MSRP was a record $US4,982, or 16.8% of MSRP.

In July, the sales-weighted average new vehicle sticker price was $29,746, $525 higher than in June 2004 and $756 higher than in July 2003. The sales weighted average net price, which is transaction price less incentives, was $24,764, $263 higher than in June 2004 and $585 higher than in July 2003.

"New models are being introduced at higher price points, but the competitiveness of the market is dramatically pushing down net prices, resulting in a record average discount," said Jane Liu, vice president of data analysis for Edmunds.com.

In July, minivans saw the largest increase at 1.7%, followed by large cars at 1.1% and compact cars at 0.6%.

"Recent sales have been particularly strong for minivans and compact cars, even considering that summer is typically their high-volume sales season," said Liu.

All SUV segments - even luxury SUVs, which traditionally have generally been immune to most of the issues that have affected SUV popularity - experienced record-setting discounts in July.

Analysts also measure the average number of days it takes to sell vehicles after they arrive at dealerships, or "days-to-turn." In July, the average was 72 days, compared to 69 in June 2004 and 73 in July 2003. Of all brands, Mitsubishi had the longest days-to-turn, 111, followed by Jaguar, 108 days. For the third consecutive month, Scion had the shortest inventory turnaround, 14 days, followed closely by Mini, 23 days.

Similar in purpose to the Consumer Price Index (CPI), the EPI-N measures the average changes in retail prices for new vehicles with fixed options over time in order to analyse trends.