Amazon Prime members are worth $143 billion to the company over their lifetimes, CNBC reports, based on an analysis by John Blackledge of Cowen and Company.
What’s more, that figure is very likely to grow: Blackledge says Prime is on track to add 12 million members in 2016, compared to 10 million last year and seven million in 2014.
He estimates that around 44% of U.S. households pay for the $99-per-year service, which includes free two-day shipping on eligible products and access to Amazon’s plentiful media library. But Blackledge told CNBC that the proportion of households who are Prime members could reach 50% by the end of the year. Data from Piper Jaffray released earlier this year indicates that more than 70% of households that earn more than $112,000 annually are members.
Read Next: Is Amazon Prime Worth It?
That’s obviously good news for Amazon, and even better when you consider that Prime members spend more on average than non-members; in fact, a report from Consumer Intelligence Research Partners puts average member expenditures at more than double what non-members spend per year.