This report builds upon a series of National Center for Education Statistics (NCES) reports on high school dropout and completion rates that began in 1988. It presents estimates of rates in 2007, provides data about trends in dropout and completion rates over the last 3 decades (1972-2007), and examines the characteristics of high school dropouts and high school completers in 2007. Four rates are presented to provide a broad picture of high school dropouts and completers in the United States, with the event dropout rate, the status dropout rate, the status completion rate, and the averaged freshman graduation rate each contributing unique information. Among findings in the report was that among reporting states in 2006, the averaged freshman graduation rate (AFGR) was 73.2 percent. The rate provides an estimate of the percentage of public high school students who graduate with a regular diploma 4 years after starting 9th grade. The report also shows that students living in low-income families were approximately 10 times more likely to drop out of high school between 2006 and 2007 than were students living in high-income families. In October 2007, approximately 3.3 million civilian noninstitutionalized 16- through 24-year-olds were not enrolled in high school and had not earned a high school diploma or alternative credential. Appended are: (1) Technical Notes; (2) Glossary; and (3) Standard Error Tables. (Contains 27 tables and 6 figures.)