between 2% and 15%
270 players were born in Venezuala and play in the MLB
According to Baseball Almanac, there has never been an MLB player that was born in Argentina.
out of 1,209 players who played at least one game in 1999, 932 were born in the USA, leaving 277 foreign born players, or 23%
As of the start of the 2007 season, there are now 9 current and former MLB players born in Alaska. Click on the 'Alaska Born MLB Players' link on this page to see a list of those players.
In the 2006 season, the MLB reported that players born outside the US made up 27.4 percent of the league. See related link for the full press release.
Mickey Mantle was from Commerce OK Johnny Bench was from Binger OK and Willie Stargell was born in Earlsboro OK. All in all 121 major league players were born in Oklahioma
According to the Baseball Almanac, in 2006 there were 978 US born players in MLB. That same year there were 399, close to 30% foreign born players. Dominican Republic had the most players, followed by Venezuela, Puerto Rico, Mexico, Canada, Cuba and Japan.
I'm not sure who has the most, but I know right now on the White Sox 25-man active roster, 20 of them are American born players.
No major leaguer has ever been born in Uruguay.