It’s looking like the third quarter was a good one for e-commerce, accordingly to monthly retail sales data released today by the U.S. Commerce Department. But Q3 likely won’t beat Q2, when e-commerce sales grew 15.8%, its largest year-over-year gain in nearly two years.

What the Commerce Department refers to as non-store sales reached $46.99 billion on seasonally adjusted basis in September, up 10.6% compared to September 2015. This is a slight deceleration from 10.9% jump in August and a big slowdown from July, when non-store sales increased 14.1% year-over-year.

For the third quarter as a whole, non-store sales were $140.71 billion, up 11.3% compared with the third quarter of last year.

Non-store sales occur mainly on the web but also include categories of retail sales that are declining, such as mail and phone orders and door-to-door sales. Thus, the growth in non-store sales is consistently lower than the growth in e-commerce sales, which the Commerce Department reports quarterly.

For example, non-store sales grew 8.6% in the first quarter while online retail sales grew 15.2%. In the second quarter, non-store sales grew 12.7% while e-commerce sales grew 15.8%.

This suggests that third quarter online retail sales jumped around 15.5% year over year. The Commerce Department releases its official third quarter e-commerce report on November 17.

Total U.S. retail sales reached $459.82 billion in September, a 2.7% jump compared with last year and 0.6% increase from August.