With plans to spend $7 billion on new and acquired content in 2018, Netflix keeps a very close eye on which programs are popular among users and which aren’t. That data is famously guarded—even content creators aren’t guaranteed access to that information—but one organization believes it has a system for gauging viewer interest on Netflix, and you might be surprised by the network's most-watched title.

According to The Hollywood Reporter, statisticians at Parrot Analytics have declared the drug drama Narcos to be the most popular original Netflix series for the month of September, followed by Stranger Things, Ozark, Orange is the New Black, and the Marvel team-up series The Defenders. The company looks at what they call “demand expressions,” which measure interest across social media and file-sharing networks to assess which shows are high in viewership.

The analysis isn’t limited to Netflix. Other digital titles across a number of platforms are also examined. For Amazon, The Man in the High Castle topped the list, with The Tick taking second place. For Hulu, the Margaret Atwood adaptation The Handmaid’s Tale and the Stephen King drama 11/22/63 took the top spots. For a given week in September, the king across all streaming platforms was Game of Thrones. Here's a snapshot:

Parrot Analytics

Naturally, only the higher-ups at Netflix and other services can confirm the accuracy of these impressions, but they rarely discuss viewership numbers. Netflix president Ted Sarandos did acknowledge the method during a press gathering in 2015, saying that Narcos is “produced by a French company, shot in Colombia with Brazilian stars, and hugely popular in Germany. This is the first flavor of what global television can be."

[h/t The Hollywood Reporter]