About half of consumers who shop online plan to buy grocery items more often in the coming year, according to a new study.

The Lake Success, New York-based Retail Feedback Group’s 2017 U.S. Online Grocery Shopper Study also found that online grocery shoppers are most satisfied with the service of Amazon. Amazon earned 4.63 out of 5 points in the study, scoring highest in categories including speed, ease of use, product availability and friendliness.

Walmart scored second with 4.41 points, and the supermarket/food store category was third with 4.32 points.

“Clearly Amazon has effectively leveraged its deep roots in online retailing to inform their efforts in online grocery, leading to the strongest ‘highly satisfied’ marks found in our research,” says Brian Numainville, a Retail Feedback Group principal.

The study also measured the strengths of online and traditional grocery shopping. The strengths of online include convenience and making the best use of time. Shopping in a physical store earned high marks for ensuring quality and freshness, selection, customer service and value.

Traditional retailers shouldn’t, however, take these advantages for granted, says Doug Madenberg, a Retail Feedback Group principal.

“Brick and mortar retailers can’t afford to be complacent as online ordering could strive to reshape these areas in the future and negate some of these advantages,” he says.