Standard&Poor's Ratings Services assigned its 'A+' standard long-term rating, and stable outlook, to District of Columbia's series 2008E and 2008F general obligation (GO) and GO refunding bonds. Standard&Poor's also affirmed its 'A+' standard long-term rating and Standard&Poor's underlying rating (SPUR), with a stable outlook, on the district's existing GO debt and its 'A' standard long-term rating and SPUR, with a stable outlook, on the district's certificates of participation (COPs). The 'A+' rating reflects the district's: Healthy and diverse economy, anchored by the federal government, military contractors, services, and tourism, as well as its role as a regional employment center; Sizable and growing property tax base that experienced strong appreciation over the past five years