Americans are increasingly doubting the value of a four-year college degree, according to an NBC/Wall Street Journal poll released Thursday.

The poll still tilts in favor of the bachelor’s degree, but by the slimmest of margins: Only 49 percent of the 1,200 adults surveyed think that a four-year degree is worth the cost because it will lead to good jobs and higher lifetime earnings. Forty-seven percent doubt it will.

Skepticism about college degrees is particularly high among men, young adults, and people who live in rural parts of the country, according to the Wall Street Journal (subscription required). Majorities of those groups doubt that a bachelor’s degree is worth the cost.

Here’s how one respondent, a Colorado mechanic who earns a base salary of $50,000 per year, put it in an interview with the Wall Street Journal:

“I have friends from high school that are making half what I’m making, and they went and got a four-year degree or better, and they’re still $50-, $60-, $70,000 dollars in debt,” Jeff McKenna told the newspaper.

Views on college were brighter just a few years ago. When CNBC asked a similar question in a 2013 poll, 53 percent said they believed the payoffs of a bachelor’s degree justified the cost, and 40 percent said it didn’t, NBC reported. That 13-point margin dropped to 2 points in this year’s poll.

In the chart below, you can see how the 2013 results (black line) differ from the 2017 results (green and pink bars). (see original link)

Some of the shift came from a subset of those surveyed: people with less than four-year degrees, the media outlets reported. Younger adults and white, working-class Americans also report particularly sharp drops in their faith in the value of a bachelor’s degree, with largely positive views in 2013 flipping to largely negative ones in 2017, the news media organizations reported.

The NBC news story includes an interesting subgroup breakdown of results, with the lowest support for bachelor’s degrees among white, working-class respondents (28 percent) and people in rural areas (31 percent).

Other groups with dim views of the value of a four-year degree were people with “some college,” only a high school diploma, or less; younger adults, men, Republicans, white people, and Trump voters.

Those with more faith in the value of a four-year degree were Democrats and independents, women, suburbanites and city dwellers, the middle class, nonwhites, seniors, Clinton voters, those with high incomes, and those with college or postgraduate degrees.

Other recent polls have found big divides in people’s views on the value of higher education. A study by the Pew Research Center in July found negative views toward higher education among most Republicans, and positive views among most Democrats. In a 2016 survey, Public Agenda found Americans increasingly believe that good jobs don’t necessarily require college degrees.

The top results from a Google search with the query “Do I need a college degree to get a good job?” are dominated by stories and reports about jobs that pay well and don’t require college degrees.

As EdWeek has reported, the public conversation about college has shifted significantly, with interest rising in career and education pathways that lead to “middle skill” jobs requiring a two-year degree or less.

On Thursday, lively debate about the new NBC/Wall Street Journal poll reflected these themes on the Journal’s Facebook page.