'the typical 6,000-square-foot Apple store rang up sales of about $4,700 per square foot in 2008, which was "undoubtedly the highest among retail chains in the country"'
Source: http://www.businessinsider.com/2009/1/apple-stores-now-just-...
Source: http://www.businessinsider.com/2009/1/apple-stores-now-just-...
Frankly, I'm still not sure that Dell or Apple would be a good choice to include here anyway; of course a place that sells $1000 - $2000 objects is going to have incredibly high revenues, and as you can see on the graph, it kind of skews it a bit...