This report updates a series of NCES reports on high school dropout and completion rates that began in 1988. The report includes national and regional population estimates for the percentage of students who dropped out of high school between 2008 and 2009, the percentage of young people who were dropouts in 2009, and the percentage of young people who were not in high school and had some form of high school credential in 2009. Data are presented by a number of characteristics including race/ethnicity, sex, age, family income, disability, and geographic region. Annual data for these population estimates are provided for the 1972-2009 period. Information about the high school class of 2009 is also presented in the form on on-time graduation rates from public high schools. Appended are Technical Notes, Glossary, and Standard Error Tables. Among the findings: Event dropout rates: On average, 3.4 percent of students who were enrolled in public or private high schools in October 2008 left school before October 2009 without completing a high school program. Event dropout rates by sex: There was no measurable difference in the 2009 event dropout rates for males and females, a pattern generally found since 1972 (tables 1 and 3). Exceptions to this pattern occurred in 4 years--1974, 1976, 1978, and 2000--when males had measurably higher event dropout rates than females. Event dropout rates by race/ethnicity: Black and Hispanic students had higher event dropout rates than White students in 2009. Event dropout rates by family income: In 2009, the event dropout rate of students living in low-income families was about five times greater than the rate of their peers from high-income families (7.4 percent vs. 1.4 percent). (Contains 28 tables, 6 figures, and 30 footnotes.) [For the previous report, "Trends in High School Dropout and Completion Rates in the United States: 1972-2008. Compendium Report. NCES 2011-012," see ED513692.]