HBO has relied on “Game of Thrones,” its most popular series ever, to drive up subscriber numbers. But while Westeros giveth, it also taketh away: The premium network has experienced notable sub declines after the fantasy epic goes off the air.

This year, however, after the conclusion of “Game of Thrones” season 7, it appears that fewer subscribers cut the cord on HBO after the dragonfire faded to black than following the previous two seasons.

Revenue generated by the HBO Now app for Sept. 16 — the first billing cycle after “GOT” season 7 concluded on Aug. 27 to record ratings — declined by just 7% compared with revenue on Aug. 16 (the billing cycle corresponding to the season premiere), according to app-research firm Sensor Tower. By the same measure, HBO Now revenue fell 22% in 2015 for season five while season six post-finale revenue from its premiere date subscribers dropped by 40%.

What explains the significantly higher subscriber retention rate? The data suggests HBO Now’s subscriber base is becoming more stable, with users keeping the service to watch additional past content or in anticipation of future series — rather than many of them showing up only to binge on “Thrones.”

It’s possible recent series such sci-fi psycho-thriller “Westworld” have “given these subscribers something to stick around for — at least for another month,” Randy Nelson, head of mobile insights at Sensor Tower, wrote in a blog post.

In addition, HBO Now may have enticed subs to stay tuned for the Sept. 10 premiere of “The Deuce,” a gritty chronicle about New York’s porn industry in the ’70s created by David Simon and George Pelacanos. HBO announced the renewal of the show, starring James Franco and Maggie Gyllenhaal, for a second season.

What’s important to note: Sensor Tower’s estimates cover only mobile-app revenue for HBO Now, excluding subscriptions via traditional pay-TV providers. Sensor Tower uses predictive models for in-app purchases, based on various data points and signals including Apple’s App Store and Google Play app rankings and actual revenue data from partners.

It’s likely that HBO’s subscribers through cable, satellite and telco operators exhibit less-volatile swings than the direct-to-consumer HBO Now product, because those pay-TV subs take the premium channel as part of a larger bundle. (HBO doesn’t release subscriber stats.)

The real test for HBO Now will be whether new series such as “The Deuce” will be “enough to hook these subscribers until the next hit rolls around,” Nelson commented.