TRENTON – Special interest money turned the 2012 elections into the most expensive in history, according to a new report issued Thursday by N.J. Public Interest Research Group.

The report, “Outside Spending, Outsized Influence,’’ said that so-called super PACS donated $2.7 million to New Jersey federal elections.

“Nationwide, Super PACs raised 86 percent of funds from an elite set of ultra-wealthy donors and businesses giving $100,000 or more,” the report said.

“Super PACs also received $101,749,662 from business corporations last year,” according to the report, which it claims lead to “attack’’ ads that distort the democratic process.

The report seeks to show the influence money from outside the state has on New Jersey elections.

“Groups federally registered outside of New Jersey accounted for 99.04 percent of all outside spending in New Jersey House and Senate races,” NJPIRG reported, adding that it believes such groups are likely to put their own interests ahead of New Jersey’s.

According to the report, the top five outside spenders in N.J. congressional races were as follows:

Patriot Prosperity PAC, $1.417 million;

Congressional Leadership Fund, $627,000;

Majority PAC, $582,000;

And two so-called “Dark Money’’ groups that NJPIRG said don’t have to disclose donors:

Patriot Majority USA, $197,000;

Our Community Votes, $105,000.