Standard&Poor's Ratings Services has affirmed its 'A' rating on the City of Austin, Texas's airport system revenue bonds. The outlook is stable. The rating reflects our assessment of the following factors: Austin-Bergstrom International Airport (AUS) has a strong origin and destination market (at 95% of enplanements) and good diversity of carriers, with Southwest Airlines Co., United Air Lines Inc., and American Airlines Inc. accounting for 74% of enplanements in 2012. There has been solid enplanement growth, with passenger traffic increasing at an average annual rate of 2.9% since 2005 to reach an all-time high of 4.72 million enplaned passengers in 2012. The airport's service area benefits from a strong economy with a low unemployment rate, an increasing population,
