Online U.S. retail sales grew by 6.4 percent to $33.6 billion over the second quarter, a 20 percent increase from the same period last year, the Commerce Department reported Thursday.

By contrast, total retail sales grew by just 1.3 percent from the first quarter and 3.8 percent from last year, the report said.

Despite the gains, online retail sales accounted for just 3.3 percent of the total retail market, which was estimated at $1,012 billion in the latest quarter.

-more briefs-