US out-of-home (OOH) ad expenditures rose 4.3% year-over-year in Q2 2012 to reach $2.05 billion, according to quarterly data released in August by the Outdoor Advertising Association of America (OAAA). This represents the ninth consecutive quarter of revenue gains for OOH advertising, although it is a small slowdown from growth rates a quarter earlier and a year earlier (each at 4.5%). OOH ad expenditures for the first half of 2012 rose by 4.4% year-over-year, to a total of $3.49 billion. Retail Posts Strongest Gains Of the top 10 industry categories tracked by the OAAA in Q2, ad spend in Miscellaneous Services and Amusements (which consists mainly of local brands), at $373 million (18.2% share), was roughly twice as high as…