Princeton’s admit rate dropped 0.7 percent to an all-time low 9.5 percent this year, in line with unprecedented numbers of applications and record low acceptance rates for all the Ivies except Yale.

Princeton administrators announced Monday that they accepted 1,791 of 18,942 applicants for the class of 2011, an applicant pool that increased 8 percent from last year. In contrast, Yale’s applicant pool decreased 9.7 percent from last year, and its admit rate rose from 8.9 to 9.6 percent this year.

Excluding Yale, other Ivies and peer institutions broke admissions records for applications and admit rates this year. Harvard University accepted 9 percent of 22,955 applicants, down from 9.3 percent last year. Columbia College and the university’s School of Engineering and Applied Sciences accepted 10.4 percent of 21,343 total applicants. Brown University admitted 13.5 percent of a pool of 19,043 applications, while the 14,159 applications received by Dartmouth College resulted in a 15 percent acceptance rate. The University of Pennsylvania admitted 3,610 students, or 15.9 percent of its 22,634 applicants, and 20.5 percent of Cornell University’s 30,383 applicants received acceptance letters. Stanford University saw a record-high 23,956 students applying and accepted a record-low 10.29 percent.

Last year, Yale admitted 1,878 total students, or 8.9 percent, out of a record-high 21,101 applications, the lowest admit rate in Ivy League history.

Dean of Admissions Jeff Brenzel said it is difficult to predict how these numbers will impact the decisions of students applying to college next year.

“On trends in admissions, it is hard to know what to expect, and I am impressed by the unpredictability of various fluctuations,” he said. “For Yale in particular, I think the changed early admissions picture for the coming fall, with Harvard and Princeton taking that option away from their applicants and Yale and Stanford keeping it open, is likely to be of some significance, but I am not aware of anyone who is making confident predictions about what will happen.”

Helen Britt, an independent counselor who used to teach at the college counselor certification program at the University of California, Berkeley, said she sees the growing number of Ivy League applications as an indication of the belief that one must attend a high-status school in order to succeed in later life.

“I think people are a lot more conscious of the idea that you’ve got to go to the best school, to Yale or Harvard or Stanford, in order to have success in life,” she said. “The idea is to go to the most prestigious school that you get into, even though it may not be the best school for you.”

The overall number of college applications is also rising, which Britt attributed to Baby Boomers’ children reaching college age and the growth of publicity surrounding college rankings and exclusivity.

Students must accept or decline offers of admission by May 1.