Some colleges and universities are more selective than others, and it’s the well-known National Universities — public or private — that have become more competitive with admissions in recent years.

“The pressure is most acute at these top universities,” says Vinay Bhaskara, co-founder of Massachusetts-based CollegeVine, which provides college admissions guidance. “Having a college degree in America has gone from a nice-to-have to something you need to have for even a lower-middle-class life in American society today.”

The increase in competition is fueled in part by the growing population of 18- to 24-year-olds in the U.S. with more students considering college; this translates to a surge in applicants that may increase a school’s selectivity — meaning lower acceptance rates.

Overall enrollment at postsecondary institutions grew from 25 percent in 1970 to 40 percent in 2014 among young adults between the ages 18 and 24, according to the National Center for Education Statistics.

“You’re seeing a lot more need for a four-year degree in terms of employment and an entry-level job,” says Ian Fisher, director of educational counseling at College Coach. The consultancy, headquartered in Massachusetts, helps students and their families navigate the college admissions process.

“There’s a lot more importance attached to a bachelor’s degree,” he says.

With increased pressure to attend college, some schools have become harder to get into than others.

[Explore college admissions trends at top National Universities in four graphs.]

Here’s an overview of some of the changing patterns in college selectivity at a range of schools from top-ranked universities, state flagship schools to smaller, private colleges.

Top-ranked schools are becoming more selective. In 1990, the acceptance rate at the University of Pennsylvania was 41 percent, according to U.S. News data. In the 2017 edition of Best Colleges, U.S. News data show 37,268 students applied to Penn and 3,787 were accepted — an acceptance rate of 10 percent.

The same change is happening across the board among the more selective schools, experts say, and many of them aren’t adding seats to accommodate demand.

Despite the growth in applications at Brown University in Rhode Island, which has seen applications rise 139 percent since 1990, the school has added only a few spots, according to U.S. News data. Total undergraduate enrollment at Brown was 5,657 in the 1989-1990 school year, compared with 6,318 in 2015-2016 — nearly a 12 percent increase over 26 years, U.S. News data show.

Brown spokesman Brian Clark says the residential college will continue its current level of growth to maintain the character of the university. Clark told U.S. News in an email, “We will continue to make investments on campus for moderate growth in a way that preserves the distinctive sense of close collaboration and connectedness that characterizes Brown.”

Some college experts say the excess in demand also fuels prestige, acting as a disincentive for these institutions to increase class sizes.

Many flagship public universities aren’t growing fast enough to meet demand, increasing selectivity. ” UNC–Chapel Hill, University of Virginia, UT–Austin, UC–Berkeley — these are the public Ivies. And even if you go to other public schools that are not the same caliber — but are the flagship in their state — you’re seeing the same type of selectivity amp up,” Bhaskara from CollegeVine says.

Some of these flagship universities accepted less than 30 percent of applicants in fall 2015, according to U.S. News data, including UC–Berkeley at 15.3 percent, University of California–Los Angeles at 17.3 percent, University of Michigan–Ann Arbor at 26.2 percent, UNC–Chapel Hill at 29.8 percent and the University of Virginia at 29.8 percent.

“Our lower offer rate is primarily driven by an increase in the applicant pool. We have experienced a 19 percent increase in applicants over the last five years while the class size for the first year class has increased 8 percent,” said Gregory Roberts, dean of admissions at UVA, in an email, who added that the number of out-of-state student applicants has also risen. “Simply put, there are more applicants for each available place in the class.”

UNC–Chapel Hill has a different acceptance rate for in-state and out-of-state applicants. The school reports that its acceptance rate has hovered around 50 percent for North Carolinians for the last 10 years, but the selectivity has increased among out-of-state applicants.

“The later has dropped below 20 percent, mainly because interest in UNC across the U.S. and the world has grown faster than the number of places we can offer to those from out of state,” Stephen Farmer, vice provost for enrollment and undergraduate admissions at UNC–Chapel Hill, told U.S. News in an email.

[Read how out-of-state enrollment is rising at state flagship universities.]

College experts say many of these schools began experiencing an uptick in applications during the Great Recession.

“The word got out that it’s a great deal,” says Jim Roche, associate provost for enrollment management at the University of Massachusetts–Amherst. “The economy helped us along the same lines and the sense that people rediscovered the great value of a public flagship university.”

The acceptance rate at UMass–Amherst has dropped from 78 percent in 1996-1997 to 58 percent in 2015-2016.

Some schools — especially smaller, lesser-known private colleges — are less selective. U.S. News data show nearly 80 percent of ranked schools accept more than half of students who apply among the 1,254 schools that submitted these data in the 2016 survey.

[Find out the 10 most and least expensive private colleges.]

“There’s an assumption that is really hard to get in to, and that’s true if you’re talking about a subset of the most selective schools in the country,” Fisher from College Coach says. “But there are a lot of places that are much closer to open enrollment or less selective.”

Wayne State College in Nebraska, for example, accepted 100 percent of applicants for the 2015-2016 school year.

Regional public institutions similar to Wayne State, which aren’t the flagship in their respective states, tend to be less selective, experts say; the other type of less selective schools are small private colleges.

Lasell College, a small residential Regional University in Newton, Massachusetts, for instance, accepted around 78 percent of its applicants last year.

“While some schools are continuously seeing a rise in application numbers, there are still a significant number of excellent small private schools that may not be seeing an influx, and therefore still ‘take a chance’ on a student that may not meet that particular school’s target,” said Kaitlyn Botelho, associate director of undergraduate admission at Lasell College, in an email to U.S. News.

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How Competitive Is College Admissions? originally appeared on usnews.com