Korea topped the list with a share of online and mobile grocery shopping taking up 16.6 percent of total purchases, more than double the proportion in second-ranked Japan (7.2 percent).

Next came the U.K. (6.9 percent), France (5.3 percent), Taiwan (5.2 percent), and China (4.2 percent). The U.S. ranked 10th with a mere 1.4 percent.

Kang Yoo-rim of Kantar said, "The younger generation who are familiar with mobile shopping lead the new consumer group, and fewer and fewer people think they have to go to the market in person to buy groceries."

She added that many busy workers prefer delivery services because they do not have time to go shopping, especially since Korea still has the longest working hours in the OECD.

