The report interviews about 70,000 customers annually to analyze customer satisfaction with more than 230 companies, giving each company, as well as sector, a score of 0 to 100.
This year, the retail sector declined 1.4% to a score of 76.8, which online retail jumped 5.1% to a score of 82.
ACSI Director David VanAmburg is not surprised by the strong performance of online retail.
"A lot of it has to do with convenience, the luxury of shopping from your home or from wherever you happen to be," he said. "On your phone or computer and looking at retail, it's just a more pleasant shopping experience in many ways."
The customers surveyed by the ACSI pointed to efficient checkout, easy navigation, page-load times, product descriptions, shipping options and breadth of merchandise as important factors for online retailers.
Last year, customers were frustrated with late deliveries, likely a result of bad weather and heavy last-minute ordering. This year retailers offered deals much earlier in the season, so there wasn't as much waiting until the last minute to make purchases. This, in turn, made it easier for retailers to deliver in a timely fashion.
Within the online sector, Amazon (AMZN - Get Report) , not surprisingly, maintained its leading position with a score of 86. Newegg and Netflix (NFLX - Get Report) tie for second place with 81, eBay (EBAY - Get Report) comes in at 79 and Overstock (OSTK - Get Report) at 77.
Overall retail struggled a bit, thanks to rising prices of things such as food and personal care.
"We had already published data in October 2014 on the merchandise those stores carry -- soft drinks, apparel, athletic shoes. We had seen satisfaction with those products drop in the fall as a result of rising prices," VanAmburg said. "It was not a big mystery to assume we would see a downturn in retail as well unless retailers were willing to bite the bullet and keep prices stable which is difficult to do because it affects their costs.
"It's going to be most keenly felt with supermarkets and drugstores, where spending is on a very regular basis and you can't avoid it because it's personal care and food," he said. "When we're seeing those prices, and they're staring us in the face on a daily or weekly basis, that's going to have a bigger impact in terms of our satisfaction."
--Written by Rebecca Borison in New York
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