According to a report by the Tax Foundation, some states receive more from the federal government than they pay in taxes on a per capita basis, while others receive less. The Tax Foundation contends that the reason for this imbalance is higher incomes in some states and a progressive income tax, which accentuates the revenue differences between high and low income states. There is, however, a relationship between the ratio of federal expenditures to tax revenues and state population. States with small populations tend to receive more money from the federal government than they pay in taxes. This can be explained by the fact that each Senator has equal bargaining power, but an unequal number of constituents with whom to share federal funds and tax breaks. Furthermore, Senators from less populous states tend to have longer term lengths than their counterparts in more populous states, which allows them become the chairmen of committees and obtain even more funds from the federal government, as well as wield more power in favor of their constituents. State population, federal funding and term length are all related and serve to deliver more wealth and power to less populous states.