to quell unrest between students and city residents and curb destructive student behavior. In addition to the Yale Police Department, a variety of safety services are available including blue phones, a safety escort, and 24-hour shuttle service. In the 1970s and 1980s, poverty and violent crime rose in New Haven, dampening Yale's student and faculty recruiting efforts. Between 1990 and 2006, New Haven's crime rate fell by half, helped by a community policing strategy by the New Haven Police and Yale's campus became the safest among peer schools. In 2004, the national non-profit watchdog group Security on Campus filed a complaint with the U.S. Department of Education, accusing Yale of under-reporting rape and sexual assaults. In April 2021, Yale announced that it will require students to receive a COVID-19 vaccine as a condition of being on campus during the fall 2021 term. Academics Admissions Undergraduate admission to Yale College is considered "most selective" by U.S. News. In 2022, Yale accepted 2,234 students to the Class of 2026 out of 50,015 applicants, for an acceptance rate of 4.46%. 98% of students graduate within six years. Through its program of need-based financial aid, Yale commits to meet the full demonstrated financial need of all applicants. Most financial aid is in the form of grants and scholarships that do not need to be paid back to the university, and the average need-based aid grant for the Class of 2017 was $46,395. 15% of Yale College students are expected to have no parental contribution, and about 50% receive some form of financial aid. About 16% of the Class of 2013 had some form of student loan debt at graduation, with an average debt of $13,000 among borrowers. For 2019, Yale ranked second in enrollment of recipients of the National Merit $2,500 Scholarship (140 scholars). Half of all Yale undergraduates are women, more than 39% are ethnic minority U.S. citizens (19% are underrepresented minorities), and 10.5% are international students. 55% attended public schools and 45% attended private, religious, or international schools, and 97% of students were in the top 10% of their high school class. Every year, Yale College also admits a small group of non-traditional students through the Eli Whitney Students Program. Collections Yale University Library, which holds over 15 million volumes, is the third-largest university collection in the United States. The main library, Sterling Memorial Library, contains about 4 million volumes, and other