With the Democratic Party convention set to get under way on Monday, Sen. Barack Obama's supporters clutch their cell phones waiting for a text message announcing who will be his running mate. Is Obama cutting it close with the length of time he's taken to noodle over who he may select or is he right on schedule?

Although John Kerry announced his selection of John Edwards 20 days before the start of the 2004 Democratic convention, other presumptive nominees since 1984 revealed their picks between four and six days preceding the event, according to data from the past 40 years. In the 1968, 1972 and 1976 conventions, the selections weren't made until three days into the conventions themselves.

The Republicans fared no different. Then-candidate George W. Bush made public his choice of Dick Cheney six days in advance of the convention. In 1996, Bob Dole chose Jack Kemp only one day in advance. Dan Quayle was chosen by Bush the Elder two days into the 1988 GOP fete.

Sen. John McCain reportedly will announce his pick on Aug. 29, three days before the Sept. 1 opening of this year's Republican gathering in Minneapolis-St. Paul.

Complete chart is here.