Despite his constant denials regarding any interest in running for Vice President on the Republican ticket with former Massachusetts Governor and presumptive GOP Presidential nominee Mitt Romney, speculation continues to swirl around New Jersey Governor Chris Christie.

A new study by Rutgers-Eagleton Institute of Politics shows recent history doesn't favor Christie as Romney's selection.

According to the Center on the American Governor (CAG), a unit of Rutgers' Eagleton Institute of Politics, from John Adams through Joe Biden, the U.S. has had 47 Vice Presidents. Fifteen of them (32 percent) previously were Governors.

Yet in modern times, looking to the pool of Governors for potential Vice Presidents seems largely to have gone out of style. Half of the first 16 and five of the next 13 vice presidents had been Governors, but only two of the 18 VPs to serve since Calvin Coolidge had histories as state chief executives.

Having two governors on the same ticket is even less common. Only six teams of Governors or former Governors have been victorious, and none since 1912, when the Democratic Governors of New Jersey and Indiana, Woodrow Wilson and Thomas R. Marshall, respectively, were elected.

John Weingart, associate director of the Eagleton Institute and one of the co-authors of the report says, "If we're sitting in New Jersey thinking about Chris Christie we can say, 'Well, the last time it happened successfully somebody from New Jersey was on the ticket."

It has been more than 60 years since a party even put forward a two-Governor ticket. In 1948 the Republican team of New York and California Governors Thomas Dewey and Earl Warren was defeated by incumbent President Harry Truman and his Vice Presidential candidate, Senator Alben Barkley of Kentucky.

"While a past or current Governor has been one of the Presidential nominees in all but one of the nine national elections since 1976," explains Weingart, "only one - Sarah Palin from Alaska in 2008 - has been a party's choice for vice president during the same period."

The Vice Presidency is actually mired in a 40-year gubernatorial slump. No Governor has been elected into the office since 1968 and 1972, when Spiro Agnew from Maryland was Richard Nixon's running mate for election and re-election; none has served since New York's Nelson Rockefeller was named to the post by President Gerald Ford in 1974 after first Agnew and then Nixon resigned amidst different scandals.

On the flip side, running for the top job when you've had experience as a state's chief executive is a good model.

"Six out of the last eight Presidents of the United States were present or former Governors," says Weingart. "In recent times being Governor and then becoming President is a god path, a well-trod path."