Freshman applications to many U.S. colleges and universities are rising this year, fueled by a surge of international students, even as costs increase and the number of U.S. high school graduates declines.

At Tufts University, international applications climbed 12 percent from a year ago and have more than doubled since 2004. The number of foreign students seeking admission to the University of California, Berkeley jumped about 22 percent this year, while the University of Pennsylvania, an Ivy League member, reported a 38 percent increase since 2010.

U.S. universities are searching overseas to fill slots with more students who can pay full tuition as the pool of domestic prospects declines and the annual cost to attend at some private colleges tops $60,000. Schools are boosting their recruiting staffs and travel budgets to pursue more international applicants.

“Having students from overseas just makes sense,” said Lee Coffin, dean of undergraduate admission at Medford, Massachusetts-based Tufts. “If the American population is going to decline, then the global population represents another source of high-quality students.”

The Western Interstate Commission on Higher Education said this month that the number of U.S. high-school graduates is expected to drop through the rest of the decade, raising questions about how colleges will recruit and enroll students. The Midwest and Northeast will experience the largest declines, according to projections in the Jan. 10 report.

Bottom Line

International students, most of whom pay full tuition, help a college’s bottom line as states cut funding to public universities and private universities struggle with lower endowment returns and rising costs.

At UC Berkeley, international and out-of-state students pay a supplemental fee of almost $23,000 a year, on top of the $11,220 tuition that Californians pay, according to the college’s website.

Universities are marketing to foreign students for pricing reasons, though increasingly those admitted are requiring a discount, said John Nelson, a managing director at Moody’s Investors Service.

“Even at a discount, the international student provides more marginal revenue to a college that otherwise might not have any added revenue from resident students who are in short supply in some parts of the country,” Nelson said in an e-mail.