UNCTAD's annual business-to-consumer e-commerce index ranked the United States again in the teens, at 13th - largely because of its relatively low share of people using the Internet compared to other developed countries.
Russia ranked 40th and China 56th while Hong Kong came in at No. 15.
The agency said Tuesday over 80% of Internet users in six European countries shop online, versus under 10% in some poorer countries.
The rankings are based on use of the Internet as well as access to secure internet servers, reliable postal services, and financial institution or mobile-money-service providers.
UNCTAD called the report provisional, cautioning that some data dates to 2017.
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