Princeton University and Yale University offered seats to the smallest percentage on record of students applying for their freshman classes.

Princeton’s 7.9 percent acceptance rate is based on a total applicant pool of 26,664, the Princeton, New Jersey-based college said today on its website. Yale, in New Haven, Connecticut, accepted 6.8 percent of 28,974 applicants, the undergraduate admissions office said in an e-mailed statement. Students have until May 1 to accept or decline at both schools.

Princeton and Harvard University reinstated non-binding early acceptance programs this year -- where students who applied in November found out in December whether they had been accepted. The early programs may have led more students to make their college choices earlier and not apply to as many schools during the regular application period. Harvard plans to release its admissions data later today.

Columbia University in New York admitted 7.4 percent of the 31,851 students who applied, Jessica Marinaccio, dean of undergraduate admissions, said in an e-mailed statement today.

The University of Pennsylvania, also in the Ivy League, admitted 12.3 percent of its undergraduate applicants, according to a statement yesterday from the school in Philadelphia.

All four colleges belong to the Ivy League, which groups eight schools in the northeastern U.S.

Princeton, founded in 1746 as the College of New Jersey, has among its alumni first lady Michelle Obama and U.S. Supreme Court Justices Samuel Alito Jr., Sonia Sotomayor and Elena Kagan.

Yale is the second richest school, behind Harvard, with an endowment of $19.4 billion as of June 30. Alumni of the school, founded in 1701, include former presidents George H.W. Bush and George W. Bush.

Both schools earn millions of dollars by sending invitations to roughly 25,000 students in which they proclaim their interest in them and end up not accepting them, but do accept their application fees.