Eighty-two percent of voters in swing states said they saw a campaign ad on TV, compared with 62 percent of non-swing-state voters, results indicated.
At the same time, swing-state voters aren't any more likely than non-swing-state voters to say they have been contacted by one of the campaigns or have been active in a campaign.
The swing-state survey included voters in Colorado, Florida, Iowa, Michigan, Nevada, New Hampshire, New Mexico, North Carolina, Ohio, Pennsylvania, Virginia, and Wisconsin -- states where results most likely will decide the election, and where much of the campaign activity is likely to be concentrated, Gallup said.
Swing-state voters supporting President Obama or presumptive Republican nominee Mitt Romney said they've had roughly equal levels of campaign contact, 37 percent and 36 percent, respectively, and campaign activity, 13 and 11 percent, the Princeton, N.J., polling agency said.
As of late June, 69 percent of swing-state voters had reported seeing a television ad that was negative toward Obama, and 63 percent reported seeing an ad negative toward Romney.
Non-swing-state voters were about as likely to report having seen negative as positive Obama or Romney ads, Gallup said.
Results are based on telephone interviews with 1,200 registered voters in swing states conducted June 22-29, representing a subset of Gallup's daily tracking survey. The margin of error for swing-state registered voters is 4 percentage points.
For results based on the sample of 577 registered voters in non-swing-states as part of Gallup Daily tracking June 25-26, the margin of error is 5 percentage points.
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