Uncollected tax revenues in any given state are the product of online sales in the state upon which taxes are not collected and the applicable tax rate. Thus, the next step in our analysis is to apportion each company’s sales among the states. We do so by assuming that individual firm e-commerce revenues are distributed across the 50 U.S. states (and Washington D.C.) in the same proportions as overall 2008 total retail sales, as reported by the Census Bureau. That is, for example, if a particular state accounts for five percent of retail commerce in the United States, we attribute five percent of each firm’s online sales to that state.