Apple Stores are successful. They’re so popular that the stores could probably be closed during the whole week of Black Friday nonsense and still make more money than 1,000 Dollar Generals.

This is something we always knew in the back of our minds, but now a research firm (with the unfortunate name RetailSails) has put out a report detailing the highest-performing retailers by sales per square foot.

Apple killed it. Their sales per square foot come in at $6,050, more than double the nearest competitor. Number two on the list happens to be a small jeweler named Tiffany & Co., which does $3,017. If the whole diamond-ring concept catches on like these iPads have, they could soon close in.

Lululemon Athletica came in third, at $1,936, proving that people are really into yoga, or at least buying apparel that makes it look like they are. Rounding out the top five were handbag retailer Coach ($1,871) and designer Michael Kors ($1,431).

All of these retailers are obviously doing an impressive job of getting customers in their doors. But in this economy, we’re going to go out on a limb here and say the Dollar Generals of the world, which might not sell items large enough make their sales psf as proportionally impressive, will still do pretty well during this holiday season.