(Image Credit: Mandel Ngan/AFP/Getty Images)

How important is the 18-29 year old vote for President Obama? Check out the huge improvement he made over John Kerry, who lost to George W. Bush in 2004, among this group of voters in key swing states.

While the percentage of the youth vote remained relatively stable, Obama's percentage of the young vote doubled and even tripled in some key states.

State - 18-29-year-olds as % of Electorate - Difference From '04 (Followed by candidate who won among 18-29-year-olds and percentage of victory)

WISCONSIN - 22% - +2%

'08: Obama + 29

'04: Kerry + 16

NORTH CAROLINA - 18% - +4%

'08: Obama + 48

'04: Kerry + 13

NEW MEXICO - 21% - +4%

'08: Obama +44

'04: Bush + 1

VIRGINIA - 21% - +4%

'08: Obama +21

'04: Kerry +8

FLORIDA - 15% - -2%

'08: Obama +24

'04: Kerry +17

NEVADA - 17% - +1%

'08: Obama +36

'04: Kerry +14

NEW HAMPSHIRE - 18% - +2%

'08: Obama +24

'04: Kerry + 14

OHIO - 17% - -4%

'08: Obama +25

'04: Kerry +14

IOWA - 17% - No change

'08: Obama +25

'04: Kerry +7

PENNSYLVANIA - 18% - -3%

'08: Obama +30

'04: Kerry +21

(Data from exit polls. Colorado not included because the state did not have vote breakdown among 18-29 for 2008.)