The university has been accredited by the New England Association of Schools and Colleges since 1929. MIT operates on a 4–1–4 academic calendar with the fall semester beginning after Labor Day and ending in mid-December, a 4-week "Independent Activities Period" in the month of January, and the spring semester commencing in early February and ceasing in late May. MIT students refer to both their majors and classes using numbers or acronyms alone. Departments and their corresponding majors are numbered in the approximate order of their foundation; for example, Civil and Environmental Engineering is , while Linguistics and Philosophy is . Students majoring in Electrical Engineering and Computer Science (EECS), the most popular department, collectively identify themselves as "Course 6". MIT students use a combination of the department's course number and the number assigned to the class to identify their subjects; for instance, the introductory calculus-based classical mechanics course is simply "8.01" at MIT. The four-year, full-time undergraduate program maintains a balance between professional majors and those in the arts and sciences, and has been dubbed "most selective" by "U.S. News", admitting few transfer students and 6.7% of its applicants in the 2017–2018 admissions cycle. MIT offers 44 undergraduate degrees across its five schools. In the 2017–2018 academic year, 1,045 bachelor of science degrees (abbreviated "SB") were granted, the only type of undergraduate degree MIT now awards. In the 2011 fall term, among students who had designated a major, the School of Engineering was the most popular division, enrolling 63% of students in its 19 degree programs, followed by the School of Science (29%), School of Humanities, Arts, & Social Sciences (3.7%), Sloan School of Management (3.3%), and School of Architecture and Planning (2%). The largest undergraduate degree programs were in Electrical Engineering and Computer Science (), Computer Science and Engineering (), Mechanical Engineering (), Physics (), and Mathematics (). All undergraduates are required to complete a core curriculum called the General Institute Requirements (GIRs). The Science Requirement, generally completed during freshman year as prerequisites for classes in science and engineering majors, comprises two semesters of physics, two semesters of calculus, one semester of chemistry, and one semester of biology. There is a Laboratory Requirement, usually satisfied by an appropriate class in a course major. The Humanities, Arts, and Social Sciences (HASS) Requirement consists of eight semesters of classes in the humanities, arts, and social sciences, including at least one semester from each division as well as the courses required for a designated concentration in a HASS division.