Updated late Friday: The Romney campaign says it will annouce the VP choice on Saturday in Virginia, at the outset of the bus tour.
Mitt Romney is bus touring through so-called "swing" states beginning Saturday, including planned stops on Sunday in North Carolina that include a barbecue restaurant in Morrisville. He'll also visit Ohio, Virginia and Florida on the four-day trip.
The bus trip is raising yet again speculation about when Romney, the presumptive Republican nominee, will annouce his running mate. Potential choices are from Virginia (Gov. Bob McDonnell), Ohio (Sen. Rob Portman), and Florida (Sen. Marco Rubio).
Might Romney announce his choice on Friday, then hit the road through key states, as John McCain did after announcing Sarah Palin as his choice in 2008? It is unclear, of course.
But here's some math that makes that scenario seem unlikely: Most of the recent choices for VP were announced in the week before the party's convention, according to an analysis by Dome of data compiled by HLNTV.com. (Find its slide show here.)
The one exception was John Edwards in 2004 -- announced nearly three weeks before that year's convention in Boston.
The GOP convention kicks off on Aug. 27 in Tampa, Fla., which is still more than two weeks after the Romney swing state bus tour begins.
If you take into account the past two decades, and exclude the Edwards choice, then VP picks have been announced, on average, about four days prior to the party's convention.
Here's when recent choices were announced:
2008: Joe Biden -- Aug. 23, two days before the convention.
2008: Sarah Palin -- Aug. 29, three days before the convention.
2004: John Edwards -- July 6, 20 days before the convention.
2000: Joe Lieberman -- Aug. 7, seven days before the convention.
2000: Dick Cheney -- July 25, six days before the convention.
1996: Jack Kemp -- Aug. 10, two days before the convention.
1992: Al Gore -- July 9, four days before the convention.