Standard&Poor's Ratings Services assigned its 'A+' rating to the District of Columbia's series 2007A and 2007B GO and GO-refunding bonds. At the same time, Standard&Poor's affirmed its 'A+' rating and underlying rating (SPUR) on the district's existing GO debt and its 'A' rating and SPUR on the district's existing certificates of participation (COPs). The 'A+' rating reflects the following strengths: The district has a healthy and diverse regional economy, anchored by the federal government, military contractors, services, and tourism, and its role as a regional employment center. There is a sizable and growing property tax base, which experienced strong appreciation over the past five years and continues to be healthy, despite undergoing a correction due to