JEFFERSON CITY, Mo. — The contentious race to succeed term-limited Missouri Gov. Jay Nixon has generated $27.5 million in television ads since last year, making it the most expensive governor’s race in the country, according to an independent analysis released Thursday.

Political newcomer Eric Greitens, who won a four-way Republican primary in August, has spent an estimated $8.4 million on ads through Monday, the Center for Public Integrity found. His general election opponent, Democratic Attorney General Chris Koster, has spent about $6.2 million in ads.

Those figures don’t include money spent making the ads or the cost of ads aired on local cable systems.

The $27.5 million figure includes millions of dollars in third-party spending, with the largest chunk of $3.9 million coming from LG PAC. The committee ran attack ads against Greitens’ former Republican opponent John Brunner, a suburban St. Louis businessman. Greitens’ campaign said the treasurer of LG PAC previously made phone calls for Greitens, but the two haven’t spoken since.

The combined total in spending also includes ads aired by unsuccessful Republican primary candidates, such as $3.8 million from Brunner and about $3.4 million from former House Speaker and U.S. attorney Catherine Hanaway.

The race between Greitens and Koster also is competitive. An Oct. 9-11 poll by Monmouth University in New Jersey found Koster ahead with 46 percent compared to Greitens’ 43 percent, although the margin of error is plus or minus 4.9 percentage points.

The competitive, open race for Missouri’s top executive position has drawn millions of dollars in donations to the campaigns of both Greitens and Kinder.

Including Missouri, there are 12 gubernatorial races this year. Broadcast TV ad spending in Missouri so far makes up about 34 percent of the total spent nationally on those races. North Carolina is second to Missouri in spending on ad buys for a governor’s race, the Center for Public Integrity found.

“It’s the kind of race that magnetically attracts all kinds of cash flow so that different sides can get some kind of an advantage in getting our attention,” University of Missouri-St. Louis political scientist Dave Robertson said.

Greitens has aired more than 20,800 ad spots and Koster more than 14,700 in the hopes of getting the attention of voters.

Robertson said Greitens’ higher spending on more ads isn’t surprising since the former Navy SEAL officer is a first-time candidate who needs to introduce himself to voters. Koster, elected twice to the statewide office of attorney general, might be saving money for a blitz of advertising closer to the Nov. 8 general election, Robertson said.

The stakes are high. Missouri’s Legislature likely will remain in Republican control next year, and Robertson said the party of the next governor will influence the fate of GOP policies. For example, a Greitens victory could revive efforts to enact a right-to-work law, which prohibits businesses and unions from reaching agreements that require all workers, not just union members, to pay union dues. Nixon vetoed such a measure this year.

“There’s a lot of interest over the policy issues that the two candidates will deal with if they become governor,” Robertson said.

Missouri also leads the nation on total ad spending for non-federal offices — an estimated $43.6 million, $20 million more than North Carolina, which is second. That total doesn’t include spending on congressional races, including a competitive Senate battle Republican Sen. Roy Blunt and Democratic Secretary of State Jason Kander.

Other statewide races in Missouri this year include campaigns for attorney general and lieutenant governor.