iPad revenues are three times higher than iPhone revenues on Apple's Newsstand

Source:  Report from App Annie, 6th September 2012
Methodology:  "The analyses and insights discussed were drawn from App Annie’s Intelligence data. App Annie takes responsibility for the claims and insights in this article that are based on this data and research. However, App Annie does not take responsibility for any actions or outcomes undertaken by 3rd parties, as a result of this article or the analyses or data contained within."