Washington, May 10 (IANS): US online retail spending reached $44.3 billion in the first three months of this year, with help from shoppers using tablet computers to buy clothing and other items, industry tracker comScore reported.

The top-performing online product categories included digital content and subscriptions, computer software, consumer electronics, jewellery, watches and event tickets.

Each category grew at least 17 percent versus year ago, reported Xinhua.

About 48.8 percent of e-commerce transactions included free shipping, the highest percentage for a quarter on record outside of the holiday season.

The online retail survey indicated Wednesday that 38 percent of US tablet computer owners have used the devices to shop online within the past month. Apparel was the most popular category for purchase among tablet shoppers.

"The first quarter of this year was especially strong for retail e-commerce as we returned to year-over-year growth rates in the high teens, numbers we haven't seen since 2007," said comScore chairman Gian Fulgoni.

"While the economic recovery continues to be painfully slow, the channel shift to e-commerce appears to be accelerating."