The mattress industry recorded unit growth last year of 3.6% and the dollar value of wholesale bedding shipments grew by 8.7%, the International Sleep Products Assn. reported.

Those figures come from ISPA's final report on 2012 industry performance, and they are significantly lower than the preliminary unit and dollar growth figures released earlier this year. The preliminary figures, based on the year-end reports of 18 producers accounting for a majority of industry shipments, envisioned unit growth of 7.6% and dollar growth of 11.7%.

But ISPA's industrywide sales survey found that smaller producers suffered unit and dollar declines last year. Those producers had a 4.7% unit decline in 2012 and a 1% dollar decline, ISPA said.

The declines of the smaller producers, and producers not participating in ISPA's monthly Bedding Barometer surveys, pulled down the industry's overall growth rates.

The final report portrays two bedding worlds, with major producers generally flying high and the smaller ones facing sales reversals.

The producers whose results are presented in ISPA's monthly reports accounted for 70% of total unit shipments last year and 78.5% of the total dollar value of bedding shipments, ISPA said. When it releases its monthly reports, it notes that those results don't necessarily reflect the results of the entire industry.

ISPA said that the final sales results left the industry slightly below (0.7%) its historical high in the wholesale dollar value of bedding shipments, reached in 2007, and well below (18.9%) its historical high in unit shipments, reached in 2005.

The report shows that specialty mattresses, including those made of memory foam, latex foam and air chambers, dramatically outperformed innerspring mattresses in 2012.

Specialty mattress units grew 18.5% last year, while innerspring mattress units grew just 1.9%. The wholesale dollar volume of specialty mattresses jumped 17.5%, while it rose 7.8% for innerspring mattresses.

But the average unit price for specialty mattresses declined 0.8% last year, to $558.67, while it grew 5.8% for innerspring mattresses to $223.78. Overall, the average unit price for the industry grew 5%, to $192.47.

ISPA said specialty mattresses now account for 16.1% of total industry units and 32.3% of the total mattress sales volume.