NASHVILLE (AP) — A new study finds that nearly $3 million has been spent on broadcast TV advertising for state-level races in Tennessee so far this year.

The report released by the non-partisan Center for Public Integrity on Wednesday found that 8,565 ads have run for and against judicial, gubernatorial and legislative candidates in the state.

The August retention campaigns of Democratic state Supreme Court Justices Connie Clark, Sharon Lee and Gary Wade involved nearly 4,600 broadcast ads. The justices and their supporters spent $929,000, while opponents spent about $538,000. Despite the bruising TV campaign, the three justices cruised to comfortable victories.

While the closing weeks of the Aug. 7 primary included a barrage of ads on the judge races, the advertising was a far cry from the 2010 election that featured $12 million in spending on 33,871 broadcast ads through the same period.

The 2010 campaign season was highlighted by an open race for governor, which was won by Republican Gov. Bill Haslam after a spirited Republican nomination fight with then-U.S. Rep. Zach Wamp and state Senate Speaker Ron Ramsey.

The Center for Public Integrity reviewed data about political advertising on national cable and broadcast television in all of the country's 210 media markets. The organization used research from Kantar Media/CMAG, which tracks political advertising and offers a widely accepted estimate of the money spent to air each spot.

These figures only represent part of the money spent on political advertising. They do not include the money spent on ads on radio, online and direct mail, television ads on local cable systems or the cost of producing the messages. That means the total cost of spending on political ads can be significantly higher.

The study found that Haslam this year spent $666,000 on about 1,900 TV ads despite not facing any serious opposition for the Republican nomination, and that advertising in state legislative races ran at about $799,000.

Knoxville surgeon Richard Briggs ran the most TV ads among the legislative candidates in his successful bid to defeat state Sen. Stacey Campfield in the Republican primary. Briggs spent nearly $190,000 to run his spots 514 times, while Campfield spent just $1,000 to run ads on broadcast television four times.

Nashville attorney Jeff Yarbro was the next-highest spender, dropping $146,000 to run 273 broadcast ads in his successful campaign for Democratic nomination to succeed longtime state Sen. Douglas Henry, who is retiring. Yarbro's opponent, Mary Mancini, spent nothing on broadcast TV ads.