Historically, local public control (and private alternatives) have allowed for some variation in the organization of schools. Elementary school includes kindergarten through to sixth grade, or kindergarten through to fifth grade, i.e., up to age 12, but some elementary schools have four or eight grades, i.e., up to ages 10 or 14 (also known as the intermediate grades). Basic subjects are taught and pupils often remain in one or two classrooms throughout the school day, except for physical education, library, music, art, and computer classes. In 2001, there were about 3.6 million children in each grade in the United States. "Middle schools" and "junior high schools" are schools that span grades 5 or 6 to 8 and 7 to 8, respectively, but junior high schools spanning grades 7 to 9 are also common.