52% of stateside Amazon customers belong to Prime

For the first time, the majority of Amazon’s customers in the U.S. belong to its Prime membership program, according to estimates by Chicago-based Consumer Intelligence Research Partners. The program had 63 million U.S. members by June’s end, bringing it to 52% of all Amazon customers in the U.S., CIRP estimates. That’s an increase of 19 million members from a year ago. As Amazon prepped for its Prime Day sales event Tuesday, the estimate may blunt one criticism from potential shoppers: that it’s available only to Prime members, who typically pay $99 for the service.

Amazon does not release a tally of Prime members, who get free two-day shipping and access to free streaming video and audio and other services. In a growing number of cities, free one-day and sometimes twohour delivery is also available.

Prime customers are vital to Amazon’s bottom line. They spend on average of about $1,200 per year, compared with about $500 per year for nonmembers, according to CIRP.

CEO Jeff Bezos said in the company’s annual letter this year that he wants to make the service indispensable so “you’d be irresponsible not to be a member,” Bezos wrote.

Prime’s numbers grew 43% in the past 12 months, up from 44 million in June 2015.

CIRP’s findings were based on surveys of 500 U.S. subjects who made a purchase at Amazon.com in the period from April to June 2016.