This report is the nation's sixth look at how its major city school systems are performing on the state assessments devised to boost standards, measure progress, provide opportunity, and ensure accountability for results. Data are presented on 66 city school systems from 38 states and the District of Columbia. The statistics are presented year-by-year and grade-by-grade on each state test in mathematics and reading between 1999-2000 and 2004-05. Data are also reported by race, language, disability, and income in cases where the state reports these publicly. Appended are: (1) Achievement Gap Trend Analysis by Grade and Subgroup; (2) Achievement Results by Grade and Subgroup, Spring 2005; (3) Grades Tested in Reading; (4) Grades Tested in Mathematics; and (5) Grades Tested in English/Language Arts. (Contains 7 tables and 12 figures.)