¹⁰Some other retail sales measures are also available from various private sources, among which the one published by Sales & Marketing Management is probably the most utilized dataset in the recent literature. These measures, nevertheless, share some common issues: the construction is not transparent and usually involves assumed models which can undermine our analysis. Denoting the retails sales measured by Sales & Marketing Management , the retail sales computed following Garrett, Hernàndez-Murillo, and Owyang (2004) , and the former combined with retail sales measures published by local government , Table 2 compares these three different measures with a benchmark denoted by , which was published by the Census Bureau but only existed for a limited time of period and 19 large states. Figure 7 and 8 compare them at the aggregate and state (Virginia) level respectively.