Amazon.com Inc. announced that it shipped over 5 billion items across the world via its subscription-based Prime service in 2017, including via one-day and two-day shipping. The e-commerce giant, which has closely guarded its Prime membership and shipping numbers, has never before released details on how many items were shipped via its Prime service across an entire year.

Amazon claimed that its Fire TV Stick and voice controlled smart device Echo Dot were the best-selling products among U.S. Prime members from any manufacturer in any category across all of its product offerings.

Amazon Prime, which offers its users services like free two-day shipping for certain purchases, unlimited streaming of movies and TV shows with Prime Video, has been attracting more subscribers every year.

The company said it shipped over 1 billion items worldwide via Prime during holiday season in 2016. Amazon Prime, which entered countries including Mexico, Netherlands, Luxembourg and Singapore last year, now is present in 16 countries around the world.

Shares of the Seattle, Washington based company were up 1.5 percent at $1,187 in afternoon trading.