This is a graph of Federal WITHHOLDING tax revenues--those derived from wages and salaries (not capgains, interest/dividends, rents.)
The decline in y/y growth began 4Q07.
Sure would be useful if the State of Wisconsin would have an on-line source for its revenue numbers, eh? At this point, only Dawn Sales-Clerk knows (?!?!?) what the Hell is going on.
HT: The Big Picture