Ad spending by Romney, Obama could reach $1 billion by election day

Ad spending by President Obama and GOP challenger Governor Mitt Romney could reach $1 billion by election day November 6. 

So far, the two candidates have spent a combined $807 on political advertising for both radio and television at the local and national levels. 

According to NBC News' analysis of ad-buying firm SMG Delta's data, Obama's team has spent $352 million on ads; "Team Romney," which is considered the Republican candidate's campaign and outside organizations supporting him, has shelled out $455 million. 

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Since September 30, political advertising has earned television stations $1.15 billion, with network and national spots upping that total to $1.33 billion, TVTechnology reported. 42.2 percent of that total was derived from presidential campaigning. 

Romney's spending continued this week, as the his team put down $13.6 million for commercial time in nine crucial swing states, including Colorado, Florida, Iowa and Ohio, CNN reported. It is one of the governor's largest ad purchases since the beginning of the election. 

Obama is outspending Romney in those states except Colorado, shelling out $16.6 million for swing state ads. 

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