This webpage from the U.S. Department of State provides a list of country reports on terrorism beginning in 2004. The list is updated annually. The webpage also provides a list of its reports on patterns of global terrorism from 2000 and 2003, as well as a link to an archive containing older reports. "U.S. law requires the Secretary of State to provide Congress, by April 30 of each year, a full and complete report on terrorism with regard to those countries and groups meeting criteria set forth in the legislation. This annual report is entitled 'Country Reports on Terrorism'. Beginning with the report for 2004, it replaced the previously published 'Patterns of Global Terrorism'."
United States Department of State: http://www.state.gov/