The indicators in this section of The Condition of Education report trends in enrollments across all levels of education. Enrollment is a key indicator of the scope of and access to educational opportunities and functions as a basic descriptor of American education. Changes in enrollment have implications for the demand for educational resources such as qualified teachers, physical facilities, and funding levels, all of which are required to provide high-quality education for our nation’s students. The indicators in this section include information on enrollment rates reported by age group, as well as enrollment by level of the education system. These levels are preprimary education, elementary and secondary education, undergraduate education, graduate and professional education, and adult education. Some of the indicators in this section provide information about the characteristics of the students who are enrolled in formal education and, in some cases, how enrollment rates of different types of students vary across schools. Indicators on participation in education from previous editions of The Condition of Education not included in this volume are available at http://nces.ed.gov/programs/coe.