amazonprimeAmazon is growing its Prime membership program faster than analysts expected.

In its quarterly earnings report posted today, the Seattle tech giant noted that paid Prime memberships around the world increased by 51 percent in 2015, and by 47 percent in the U.S.

Amazon CEO Jeff Bezos.
Amazon CEO Jeff Bezos.

The growth is consistent with 2014, when Prime memberships grew by 53 percent.

“We are very happy with the growth,” Amazon CFO Brian Olsavsky said on a conference call with journalists today. “We just continue to make the program as valuable as we can.”

Earlier this week, the Consumer Intelligence Research Partners (CIRP) group predicted that Amazon increased its U.S. Prime membership base by 35 percent in 2015. It also predicted 54 million U.S. Prime members. Amazon did not reveal exactly how many Prime members exist today, but analysts say there are between 60 to 80 million.

Increasing the number of Prime members is a big deal for Amazon. Members spend more on average, about $1,100 per year compared to the $600 per year for non-members, CIRP said its report. Prime members also tend to be more loyal, and Amazon retains approximately 95 percent of them after one year, CIRP said in July.

“We are focused on making this a great program,” Olsavsky said. “As you can see, customers are responding, and when they do, we see an increase in spend and interaction with Amazon going forward.”

Prime members pay $99-per-year to receive free two-day shipping as well as other benefits, including access to the company’s video-streaming subscription service, music streaming, photo storage, and more. There are more than 30 million items eligible for free two-day shipping for Prime members.

Shares of Amazon are down more than 10 percent in after-hours trading today after the Seattle tech giant missed analyst expectations for profit and revenue during the 2015 holiday quarter.

Like what you're reading? Subscribe to GeekWire's free newsletters to catch every headline

Job Listings on GeekWork

Find more jobs on GeekWork. Employers, post a job here.