Amazon has revealed membership numbers for its Prime subscription service for the first time.

More than 100 million people are now members of Prime, chief executive Jeff Bezos revealed in his annual letter to shareholders.

Until now, Amazon had only disclosed that it had “tens of millions” of Prime customers.

Prime has been one of Amazon’s biggest innovations, providing members with access to enhanced fulfilment options and services. Members tend to spend more with Amazon than non-members.

Robert W Baird & Co analyst Colin Sebastian told The Wall Street Journal that the number of Prime users was “in-line to slightly above expectations”.

Last year Amazon brought in $9.72bn in revenue directly from subscription services, including fees from Prime members.

Bezos’ shareholder letter also revealed that more new members joined Prime last year than in any previous year. The service has been rolling out internationally and last year was launched in countries including Mexico, the Netherlands and Singapore.