Sales taxation has, in the course of 25 years, become the chief single source of state tax revenue, now yielding about 2.5billionor21percentoftotalstatetaxrevenueinthe1955fiscalyear.2˘7Inthe31statesusingthetax,ityieldsapproximatelyonethirdofstatetaxrevenues,withyieldsofover40percentinWashington,Georgia,Michigan,andMissouri.Thetaxhasalsobeengrowinginimportanceatthelocallevel,nowyieldingabout400 million, the bulk of this being obtained by a relatively few large cities. The federal government has never employed a general sales tax, despite considerable pressure for the tax at various times. Such taxes are used extensively by other national governments in various parts of the world--but in most of these countries there is no similar use at lower levels of government