Standard&Poor's Ratings Services affirmed the 'A-' rating on the San Francisco (Calif.) City&County Port Commission's senior revenue bonds. The rating reflects the port's strong competitive position in the San Francisco real estate market, its low debt burden and short debt maturity, and its susceptibility to local economic downturns. More specifically, the rating reflects the following credit strengths: Limited competition for the port's real estate properties, consisting of about 7.5 miles of San Francisco waterfront. Low debt burden with a short debt maturity occurring in 2009, before the expiration date of most of the port's largest leases. No additional debt requirements under the current capital plan. The following credit concerns offset these credit strengths: Declines in debt