Standard&Poor's Ratings Services assigned its 'A' rating to the Port of Oakland's $514.34 million series 2007A, 2007B, and 2007C intermediate lien refunding revenue bonds. In addition, Standard&Poor's affirmed its 'A+' rating on the port's outstanding senior lien revenue bonds. The ratings on the port's bonds are based on the diversity of the revenue base, which includes the airport, the marine port, and the commercial real estate division. The airport's stable O&D passenger base and solid coverage levels also support the ratings More specifically, the ratings reflect the following strengths: Revenue diversity that is provided by a gross pledge of all port money, including airport (50.3% of gross revenues), marine port (45.8%), and real estate development (3.9%)--even