For the first time, Amazon has revealed just how popular Prime is; globally, the paid subscription service has attracted more than 100 million members.

The total subscriber count was revealed in a Wednesday letter to shareholders from Amazon CEO Jeff Bezos.

“In 2017 Amazon shipped more than five billion items with Prime worldwide, and more new members joined Prime than in any previous year —both worldwide and in the US,” he wrote.

Bezos didn’t offer details about the membership growth, but his company has been expanding Amazon Prime(Opens in a new window) to new countries including Mexico, Singapore, and the Netherlands.

Those who subscribe to Amazon Prime ($99 a year or $12.99 a month) get free two-day shipping on eligible Amazon.com purchases and access to services like Amazon Video, Prime Music, and more.

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Amazon started the program 13 years ago when an engineer named Charlie Ward pitched(Opens in a new window) the idea through a company employee-suggestion box. It has long declined to reveal exact subscriber numbers; recent estimates put it at 80 million(Opens in a new window) or 90 million(Opens in a new window) members in the US.

We still don’t have exact numbers on Amazon’s hardware sales; Bezos said only that “2017 was our best year yet for hardware sales. Customers bought tens of millions of Echo devices.”

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