U.S. e-commerce sales in the third quarter were $87.51 billion, up 15.1% from $76.04 billion in the same period of 2014, according to the U.S. Commerce Department’s seasonally adjusted estimates. E-commerce accounted for 7.4% of total retail sales, excluding foodservice (sales at restaurants and bars) during the period, but 60% of the growth of the U.S. retail sector.

Total retail sales excluding food service for the quarter ended Sept. 30 were $1.185 trillion, a 1.6% increase from $1.166 trillion in Q3 2014, the Commerce Department said Tuesday. The nearly $11.5 billion in online retail growth accounted for just over 60% of the $19 billion in total retail sales growth for the quarter.

When further excluding sales of autos and fuel, items not typically bought online, Internet Retailer calculates that e-commerce accounted for about 9.5% of total adjusted sales during the third quarter, up from 8.3% a year ago.

On an unadjusted basis, Q3 e-commerce sales, excluding foodservice, totaled $81.05 billion, up 15.2% from $70.35 billion in Q3 2014, according to the Commerce Department. Total retail sales were $1.19 trillion, up 1.6% from $1.17 trillion in the year-ago quarter.

Internet Retailer’s calculation excluding sales of autos and fuel show online sales accounted for about 8.8% of total non-adjusted retail sales in the quarter, up from 7.7% a year ago

For the first nine months of the year, adjusted U.S. e-commerce sales totaled $251.98 billion or 7.2% of total retail sales (excluding foodservice) of $3.51 trillion, according to Commerce Department data. On an unadjusted basis, web sales for the first nine months of the year totaled $234.75 billion, or 6.8% of total retail sales (excluding foodservice) of $3.45 trillion.

In July, market research firm eMarketer projected global e-commerce sales will eclipse $3.5 trillion within the next five years, with the web accounting for 7.3% of global retail sales this year, growing to 12.4% by 2019.