WASHINGTON — More than 60,600 campaign ads — including some 4,600 in the last week — have aired in Arkansas’ hotly contested U.S. Senate race in what has been one of the nastier air battles of this election cycle.

WASHINGTON — More than 60,600 campaign ads — including some 4,600 in the last week — have aired in Arkansas’ hotly contested U.S. Senate race in what has been one of the nastier air battles of this election cycle.


The Arkansas contest trails only North Carolina in the percentage of "negative" ads that have been aired, according to a study released Thursday by the Wesleyan Media Project. Since September, 65.5 percent of the Arkansas ads were negative attacks of either Democrat Mark Pryor or Republican Tom Cotton. In North Carolina, 65.8 percent of the ads were negative.


The nonprofit group based at Wesleyan University in Middletown, Conn., which has been tracking campaign ads for several election cycles, said that negative ads still dominate political campaigns but are leveling off.


"Since 2000, the percentage of negativity has been rising in each election cycle, but it seems we may have finally reached a plateau," said Erika Franklin Fowler, co-director of the Project. "Negativity this cycle has been comparable to past levels. Gubernatorial ads are more negative this year than they have been previously, but House ads are less negative. Senate ads are slightly more negative than 2010 but less negative than 2012. Any way you count them, however, attack ads continue to dominate the airwaves."


The latest review of ads that have run since Sept. 1, categorized the content as "negative," "positive" or "contrast." The latter category describing an ad that provided a contrast between competing candidates rather than promoting or attacking a particular candidate.


Among the dozen Senate races studied, Arkansas was second in negative ads but also ranked first in positive ads at 27 percent. Only 7.6 percent of the ads were "contrast" ads — lowest among the dozen races, according to the study. Louisiana had the lowest percentage of "positive" ads at 14.3 percent but topped the list for "contrast" ads at 47.9 percent.


A review of gubernatorial contests found Arkansas in the middle with 36.9 percent "positive" ads, 28.6 percent "contrast" and 34.5 percent "negative." Connecticut had the most negative gubernatorial race with 69.6 percent "negative" ads and just 15 percent "positive."


The report also found the Little Rock media market ranked second in the nation in campaign ads, with 51,758 spots having aired at an estimated cost of $25.4 million. Denver topped the ranking with 78,386 spots run at a cost of $77.6 million. The total includes all campaigns.


In Arkansas, the U.S. Senate races had dominated the air waves as the national parties and special interest groups pour millions into the campaign. Republicans need to pick up six seats this mid-term to gain the majority in the U.S. Senate — and Arkansas is among the GOP’s strongest targets. Pryor is the lone Democrat in the Arkansas delegation to Congress — a sharp turnaround from six years ago when no Republican challenged Pryor and the state’s delegation included five Democrats and a single Republican.


More than 60,600 Senate campaign ads — including some 4,600 in the last week — have been broadcast in Arkansas, according to the latest tally from the Center for Public Integrity.


Pryor and his supporters have spent $12.4 million to run 30,700 ad spots on broadcast outlets in the state. Meanwhile, Cotton and his supporters have spent $14 million to run 29,900 ads, according to data provided to CPI by Kantar Media/CMAG.


Those figures may be conservative, according to Reid Wilson of the Washington Post. He estimates that as much as $46 million has been spent in Arkansas on campaign ads for the U.S. Senate. The estimate Wilson said is based on information from ad buyers rather than CMAG or other ad monitoring groups.