Which jewelry and luxury retailers have the highest sales per square foot? Here's the ranking from the eMarketer Retail and Ecommerce database.

1. Tiffany & Co. - $2,699

2. Kate Spade & Co. - $1,523

3. Birks Group - $1,489

4. Michael Kors - $1,269

5. Coach - $1,237

6. Signet Jewelers - $987