RALEIGH, N.C. — The North Carolina governor’s race is living up to expectations of being an intense, expensive political fight across the state’s airwaves.

A review of political advertising on broadcast television in North Carolina shows tens of thousands of ads have been run by Republican Gov. Pat McCrory, Democratic challenger Roy Cooper and allied groups since their primary victories March 15. The overall cost of the ads is estimated at $18.6 million, according to data released Thursday by the Center for Public Integrity.

With pre-primary spending added in, North Carolina’s $19.4 million ranks second only to Missouri at an estimated $27.2 million for broadcast TV spending in a gubernatorial race, the center’s figures show.

Nearly 60 percent of the more than 34,000 spots since the primary analyzed and related to the race have come from Cooper, the sitting attorney general, or from independent political groups backing him, according to the center. It analyzed advertising data from Kantar Media/CMAG, a media tracking firm.

TV ads addressing a law McCrory signed last March that limited local governments in passing anti-discrimination ordinances for LGBT people have aired but aren’t extensive. The law known as House Bill 2, or HB2, also directed transgender people to use bathrooms and locker rooms in schools and government buildings corresponding to the sex on their birth certificate. Cooper wants the law repealed.

Cooper’s campaign has outraised McCrory since early 2015, leaving him with more cash to spend on ads in a gubernatorial race considered among the nation’s most competitive. Several polls have shown the race too close to call or place Cooper slightly ahead in the presidential battleground state where ads for the U.S. Senate race between Richard Burr and Deborah Ross also blanket TV channels.

From after the primary through earlier this week, Cooper had aired more than 13,800 spots estimated to cost $7.8 million, the center said. McCrory’s campaign had run about 7,400 ads at a cost of $4.5 million during the same period, the center added.

The Republican Governors Association has helped close the gap, running more than 6,400 spots so far at an estimated $1.8 million, the center said. The RGA has generally run attack ads criticizing Cooper for his management of the state crime lab since becoming attorney general in 2001.

Several outside political committees — some funded by environmental groups and the Democratic Governors Association — also have been on the offensive against McCrory. The Natural Resources Defense Council (1,626 spots since the primary) and Conservation Votes PAC (493 spots) have accused McCrory in ads of failing to clean up coal ash pits or giving a break to ash owner Duke Energy, McCrory’s former employer.

The center said NC Families First, which ran an ad last spring with funding from the Democratic Governors Association highlighting economic hits the state took after House Bill 2’s passage, has aired over 1,000 spots. A pro-House Bill 2 group called the Institute for Faith and Family also is running ads and released a commercial this week praising the law.

Data from Kantar Media/CMAG comes from 211 media markets it monitors around the country — including all those covering North Carolina — and offers a widely accepted estimate of the money spent to air each spot. The ads represent only part of the money spent on political advertising. They do not include ads for radio, online, direct mail or TV ads that aired on local cable systems. The monetary estimates also do not include the cost of making the ads.