The amount, which includes spending by candidates and outside groups, is nearly 40 percent higher than the previous record of $20.2 million spent in 2008. The legislative campaigns and fundraising committees spent $19.1 million, up from a record $13.1 million in 2008.

Groups that back Democrats spent $4.8 million compared with $4.2 million spent by groups that support Republicans. Republicans expanded their majorities in both the Assembly and Senate.

Supposedly independent outside groups spent $9 million, breaking the previous record of $7.1 million in 2008.

“The record spending in the 2016 legislative races was likely due to sweeping changes to state campaign finance laws in 2015 that doubled candidate contribution limits, and allowed corporate contributions to parties and legislative fundraising committees, among other things,” according to the Democracy Campaign, which tracks campaign donations and spending.

More than $5 million was spent on the race for the open 18th Senate District seat, in which Republican Dan Feyen defeated Democrat Mark Harris. Both candidates were among the four statewide who spent more than a half million dollars. Wisconsin Manufacturers & Commerce, which backs Republicans, spent $1.4 million and the Greater Wisconsin Committee, which backs Democrats, spent $1.3 million.

Overall, the Greater Wisconsin Committee spent the most statewide on Democratic candidates and supposedly independent issue ads with $2.1 million. WMC spent $1.8 million. Another group backing Democrats, Prosperity for Everyday People, spent $1.1 million, as did the American Federation for Children, which backs Republicans.

Democrat Brian Smith’s campaign spent $580,400, the most of any candidate in the state last year. Smith lost to incumbent Republican Sen. Luther Olsen, R-Ripon.

It was the second-most spent by a Wisconsin legislative candidate ever, behind the $722,333 spent by Democratic Rep. Sheldon Wasserman in an unsuccessful attempt to unseat Republican Sen. Alberta Darling in 2008.

Nearly three dozen candidates spent more than $100,000 last year. That’s up from 27 in 2008.

The race for the 14th Senate District drew the second-most spending with about $3 million. The most expensive Assembly race was the 51st Assembly District, in which incumbent Republican Rep. Todd Novak, R-Dodgeville, defeated Democratic challenger Jeff Wright. Total spending topped $1.4 million, with Novak’s campaign spending $510,460, the most for an Assembly campaign last year.

Sen. Jon Erpenbach, D-Middleton, said even though Democratic-supporting groups outpaced Republican groups, Democrats oppose the increases.

“Overall we’d rather see less money involved and more disclosure of everybody involved,” Erpenbach said. “It was very much a Republican piece of legislation and as a result we have record amounts of spending.”

Assembly Minority Leader Peter Barca, D-Kenosha, noted the changes in campaign finance law make it impossible to know how much was actually spent on the 2016 races.

“It is essential to restore transparency and accountability back into our campaign finance system — the barrier for citizens to enter into politics should not have such a high price tag,” Barca said.

Assembly Speaker Robin Vos, R-Rochester, and Senate Majority Leader Scott Fitzgerald, R-Juneau, didn’t respond to a request for comment.