“Titanic” turns 20 years old today, and we haven’t had a film much like it since. It was a global phenomenon. It wasn’t built on a pre-existing franchise. And it turned into one of the most iconic films ever produced.

It was nominated for 14 Oscars and won 11. Its legs were legendary: “Titanic” didn’t make its billions all at once up front, it made them week after week after week. The film had the biggest ninth weekend at the domestic box office in history, then the biggest 10th weekend, and so on and so forth through its 18th weekend. The film clocked in 15 weeks as the No. 1 film at the domestic box office. Paramount shipped an estimated 24 million units to video stores in 1998 to brace for the home video sales market. Its television rights sold for $30 million, but that figure was considered so low it launched an internecine industry fight.

So as its anniversary was approaching, we started wondering in the FiveThirtyEight office: Has anyone not seen this movie?

As such, we added two questions to a SurveyMonkey Audience poll of 1,009 respondents in the U.S. aged 18 and up. We asked: Have you seen “Titanic?” And, if so, did you first see it in a theater?

It turns out that far more people had seen the film than I originally imagined. Eighty-five percent of respondents said they had seen “Titanic”; 15 percent said they had not. That’s an impressive figure. For perspective, only about half of America watches a given Super Bowl, tops. As far as I can tell, the rate of “Titanic” viewership sometime in the last two decades is roughly on par with computer or Bible ownership.

‘Women and children toward the front, please’

There is not much of a gender split. I thought there might be, but men were slightly more likely to say they had seen “Titanic” in theaters, and women were slightly more likely to have seen it overall. “Titanic” is one of those rare four quadrant hits: young and old, male and female alike have seen this thing.

I think that’s a strong part of the movie’s appeal. Remember that the film’s first 20 minutes is essentially a swashbuckling treasure heist starring Bill Paxton trying to find a diamond. Jack doesn’t even see Rose until 35 minutes into the film, and from then on it’s only a little over an hour of romance until the iceberg shows up and it turns into a seat-of-the-pants action and disaster movie. It really has something for everybody.

Age brings in another angle. The older the respondent was, the more likely they were to have seen the film in a cinema, but — and here’s the fascinating part — the less likely they were to have seen it, period. About 90 percent of women aged 18 to 29 and 30 to 44 had seen the film, the highest viewership rate among all groups. They’d have been in their early 20s or younger when the film was in cinemas, and most of the former group had grown up with “Titanic” as a cultural phenomenon all their lives.

On the other end, only about 3 in 4 men age 60 and higher said they had seen it, making them the least likely group. (These guys would have been in their 40s and up when “Titanic” was released, and about two-thirds of the ones who have seen the film said they saw it in theaters.)

Given these age and gender figures and census data for 2016, and assuming they scale nationally, I’d estimate that about 39 million American adults haven’t seen “Titanic” while about 211 million have at some point in their lives.

‘Will the lifeboats be seated according to class?’

My favorite finding of the poll? This is a movie about a relationship with a staggering wealth disparity, but the richest and poorest respondents were the least likely to have seen the film. Among respondents in households who make $50,000 to $74,999, 92 percent said they had seen the film. Only 81 percent of those who live in households making $150,000 or above and 82 percent of those making $24,999 and below said they’d caught the movie.

All this has left me a bit curious about that 15 percent of people who have managed to avoid seeing “Titanic” for each of the last 20 years.

I found one.

“Basically, I was 7 when it came out; shockingly my mother was against me seeing a film with a naked woman,” said Heather Antos, an editor at Marvel who recently confided to me that she had not seen “Titanic.” “Beyond that, I’ve just never been interested in it. I know the story. What’s left other than sitting around for three hours?”

That’s three hours and 14 minutes, thank you very much.