On the revenue side, the degree to which federal taxation absorbs shocks at the state level cannot be very large for the simple reason that the main source of federal revenues that does react to the business cycle, the federal income tax, accounts for less than 10% of GDP.
从收入端看，联邦税吸收州层面冲击的程度不可能很大，原因很简单：会对商业周期做出反应的联邦收入主源——联邦所得税只占GDP的不到10%。