Just had a looksie b/c of the Arlington-Alexandria debate.

Arlington HSs had more than 90% of students graduate on time (the state average is 86.6%)

At T.C. Williams in Alexandria it was 79.2%.

Data here:
http://www.doe.virginia.gov/statistics_reports/graduation_completion/cohort_reports/index.shtml

(You have to download the spreadsheet for "Schools with a Graduating Class (four-year cohort report).)