Online retailer Amazon.com Inc (AMZN.O) said on Tuesday it shipped over 5 billion items worldwide via its subscription based Prime service in 2017 while adding more new members than ever before.

The e-commerce giant, which revealed its Prime shipment numbers for the first time, did not give comparable full-year shipment number for 2016.

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.