The Common Core of Data (CCD), an annual universe collection of public elementary and secondary education data, provides an event dropout number and rate. An event dropout number is the number of students dropping out in a single year, and the event dropout rate is the percentage that dropout in a single year. A total of 540,382 PS students dropped out of grades 9-12 in school year 2004-05 in the 50 States. In the 2004-05 school years, PS event dropout rates for grades 9-12 varied from a low of 1.9 percent in North Dakota to a high of 8.2 percent in Alaska. The PS grade 9-12 event dropout rate for the reporting States as a whole was 3.9 percent. More males (289,675) than females (209,818) dropped out of grades 9-12 in school year 2004-05. For dropouts for whom race/ethnicity was reported in school year 2004-05, 2.1 percent were American Indian/Alaska Native, 2.9 percent were Asian/Pacific Islander, 26.4 percent were Hispanic, 27 percent were Black non-Hispanic, and 41.5 percent were White non-Hispanic. Nationally, American Indian/Alaska Native PS students were more likely to drop out of grades 9-12 than were students in the other racial/ethnic groups; however, in the Northeast and the South, grade 9-12 event dropout rates for Hispanic and Black non-Hispanic students exceeded those of American Indian/Alaska Native students. Public school students in grades 9-12 were less likely to drop out of school in the Midwest (3.4 percent) and most likely to drop out of school in the West (4.1 percent). For all regions, location of the district in large cities compared with less urbanized areas was associated with higher event dropout rates. 7 tables, 4 references, and 2 appendixes