The Obama and Romney campaigns are likely to spend $1 billion to air 1 million-plus ads by Election Day, a UPI analysis of a U.S. university study indicated. The campaigns of President Barack Obama and Republican presidential nominee Mitt Romney already set a record by running more than 915,000 commercials on broadcast and cable stations from June 1 to Oct. 21, the Wesleyan Media Project study found. The airtime cost of those ads was about $900 million, The Daily Beast said the Wesleyan analysis indicated. The number of political ads in that 143-day period represented a 44.5 percent jump from the 637,000 ads aired in the same period of 2008 and a 43.7 percent increase from the 634,000 ads aired that period in 2004, the study found. Presidential political advertising typically increases dramatically in the final days before the election, but if the current advertising-frequency rate simply continues at the average pace of the days the Wesleyan researchers studied, the two campaigns would be on trend to reach 1 million ads Nov. 3, three days before Election Day, the United Press International analysis indicated. The advertising money spent for to air those ads would top $982 million that day and go over the $1 billion mark two days later, the day before the election, the UPI analysis indicated. \"When all is said and done, 2012 will go down as a record pulverizing year for political advertising,\" media project Co-director Erika Franklin Fowler said. \"We\'ve already surpassed the total number of presidential ads aired during the entire 2008 campaign,\" she said. The campaign still has 12 days to go before the Nov. 6 election. \"What is especially striking is that the ads are concentrated on fewer markets than 2008, meaning that a smaller number of Americans have witnessed the onslaught of messages in the race for the White House,\" said Fowler, an assistant professor of government at Wesleyan University in Middletown, Conn. Las Vegas, Denver and Cleveland have been the epicenters of presidential advertising this year, the Wesleyan study indicated. Miami, Orlando and Tampa, Fla., and the District of Columbia are also top markets this year for campaign ads, the researchers said. In the first three weeks of this month, pro-Obama ads outnumbered pro-Romney ads, 112,000 to 97,000, with pro-Obama ads leading in 13 of 15 top media markets. Pro-Romney ads had a slight advantage in two key battleground markets -- Columbus, Ohio, and Norfolk, Va. -- while Obama led in Denver, Las Vegas and Orlando, Fla. \"One reason Obama has been able to win the air war in most media markets is that his campaign is funding most of its own advertising, which entitles his campaign to the lowest rate charged by local television stations,\" said media project Co-director Travis Ridout. \"By contrast, many ads supporting Romney are paid for by outside groups, which must pay whatever the market will bear to get their ads on the air.\" The researchers also observed that the advertising this year is highly negative, with Obama ads more negative than Romney ads. Eleven percent of Romney campaign-sponsored ads and 6.3 percent of Obama campaign-sponsored ads airing Oct. 1-21 were positive, meaning they spoke only about the sponsoring candidate, the study found, while 52.1 percent of ads sponsored by the Romney campaign were negative \"contrast ads,\" as were 63 percent of ads sponsored by the Obama campaign. The Wesleyan Media Project is supported by grants from the John S. and James L. Knight Foundation, the Rockefeller Brothers Fund and Wesleyan University.