Netflix is spending a pretty penny on original entertainment — but while that stuff grabs most of the headlines, it’s actually licensed titles like TV show reruns that still form the core of the company’s streaming business.

That’s according to a data analysis from 7Park Data, which found that 80% of Netflix U.S. viewing is from licensed content with 20% from original shows like “House of Cards” or “Stranger Things.” The firm also found that 42% of Netflix subscribers watch mostly licensed content (95% or more of their total streaming). Just 18% of Netflix’s U.S. streaming customers are “originals dominant,” whose viewing comprises 40%-100% of originals, according to 7Park. The data is for the 12-month period that ended September 2017.

Top licensed titles on Netflix for that period included “Breaking Bad,” “Grey’s Anatomy,” “The Blacklist,” “How I Met Your Mother,” “The Office,” “Parks and Recreation,” “Criminal Minds,” “Supernatural,” “The Flash,” and “Friends.” (Note that “How I Met Your Mother” rolled off Netflix and moved to Hulu in November 2017 under a deal with 20th Century Fox Television.)

For Hulu, which has fewer original series than Netflix, the ratio of licensed-to-original content viewing is even higher: 97% of Hulu streams were from licensed content for the 12 months ended September 2017. Hulu’s biggest breakout success to date has been award-winning series “The Handmaid’s Tale,” based on Margaret Atwood’s novel.

Moreover, while originals play an important role in driving new subscriptions, even here licensed content has the edge: 58% of new Netflix U.S. subs watched licensed programming first, while 89% of Hulu subs did.

Even when Netflix debuts a much-hyped new show, licensed content remains the bulk of U.S. customers’ viewing. For example, in the seven days after “Stranger Things” season 1 debuted, licensed shows were still 63% of TV viewing; in the week following the premiere of “Black Mirror” season 3, around 88% of TV series viewing was licensed content, 7Park found.

There aren’t public numbers on what the tonnage is of Netflix’s originals vs. licensed content. It’s possible that original TV shows and movies overindex in terms of viewing — but the point is, for all the noise about Netflix originals, the bulk of its value proposition for consumers is still largely in second-run (or later) content windows.

Reps for Netflix and Hulu declined to comment on the 7Park report.

Of course, as with other attempts to measure SVOD services, some caveats are in order about the limitations of 7Park’s methodology. Most significantly, the research firm’s panel measures only desktop viewing — excluding mobile and connected-TV platforms. (According to 7Park, it has conducted “extensive testing” of its data against industry metrics for mobile and connected TV platforms, indicating that the data is “highly representative of all viewership, regardless of platform or device.”) Meanwhile, 7Park claims to have more than 2 million panel members in 50 countries, but it doesn’t disclose how many it has in the U.S. or what the margin of error is for the latest study.

That said, there’s no denying that licensed content remains a key part of the lineup for Netflix, Hulu, Amazon Prime Video and other services. Such programming is popular because there’s already a broad awareness among consumers of TV shows like “Breaking Bad” or “Grey’s Anatomy.” Plus, in a subscription VOD streaming environment, viewers are able to binge-watch full seasons — and they don’t have to watch ads.

“Licensed content is the engagement engine that drives SVOD viewership, retention and revenue,” commented Christopher Coby, senior industry analyst at 7Park Data.

Even so, Netflix isn’t taking its foot off the gas on the originals front. CFO David Wells projected the company will have some 700 original series total globally this year. Netflix, which expects to spend up to $8 billion on content in 2018, has set a long-term target of allocating 50% of its content budget to originals.

The company’s strategy continues to be, “Let’s continue to add content — it’s working, it’s driving growth,” Wells said at an investor conference in February.

And in fact, Netflix’s booming slate of original content is moving the needle. For the 12-month period ended September 2016, just 12% of U.S. streams were Netflix originals — increasing to 20% the following year, per 7Park’s study.

New York-based 7Park Data, founded in 2012, is backed by investors including Mueller Ventures. The company sells data tracking Netflix, Hulu and Amazon VOD viewing to clients across the entertainment industry including studios, TV networks, production companies, and talent agencies.

Per 7Park’s analysis, the most popular Netflix originals for the 12 months ended September 2017 included: “Stranger Things” season 1, the fifth seasons of “Orange Is the New Black” and “House of Cards,” “Marvel’s Luke Cage,” “Marvel’s The Defenders,” “Marvel’s Iron Fist,” “13 Reasons Why,” “Ozark,” “Santa Clarita Diet,” “A Series of Unfortunate Events,” “Master of None” season 2, “Narcos” season 3, “Grace & Frankie” season 3, “Black Mirror” season 3, “The Unbreakable Kimmy Schmidt” season 3, and “Bojack Horseman” season 4.