The super PAC that has spent nearly $1 million to support Democrats in New Jersey's Assembly elections next month has received nearly 90 percent of its money from a group affiliated with the state's largest teachers' union, records filed with state regulators show.

Washington-based General Majority PAC has raised about $3.1 million and used the cash to broadcast cable TV ads supporting Democrats and attacking Republicans in South Jersey's First and Second Districts at the Shore, as well as in Bergen County's 38th District.

Most of that fund-raising haul came from Garden State Forward, an outside group affiliated with the New Jersey Education Association, according to records filed with the state Election Law Enforcement Commission (ELEC).

The group contributed $2.75 million to General Majority, according to the filing, made public Tuesday.

Another super PAC, New Jerseyans for a Better Tomorrow, gave $25,000. That PAC is chaired by Sean Kennedy, a former aide to Senate President Stephen Sweeney (D., Gloucester). Sweeney is a likely gubernatorial candidate in 2017.

ELEC said there was no evidence an independent-expenditure group was backing Republicans in these districts.

Overall, with all 80 seats up for grabs, Democratic candidates have spent about $5 million this cycle and Republicans $1.6 million.

In the First District, for example, Democratic incumbent Bob Andrzejczak and running mate Bruce Land have spent $467,000, outpacing their GOP opponents, incumbent Sam Fiocchi and Jim Sauro, who have spent $110,000.

So-called super political action committees can raise unlimited sums from individuals, corporations, and unions, but cannot coordinate their spending with the campaigns.

General Majority PAC, which has spent about $2 million this cycle overall, including on administrative costs, legal expenses, and polling, is voluntarily disclosing its donors. (At the federal level, such disclosure is required.)

ELEC's preliminary analysis of campaign-finance filings found that spending by outside groups has accounted for 45 percent of the nearly $12 million spent on the general election thus far.

"Usually, an election with just Assembly candidates on the ballot is a low-key affair. But the involvement of the independent committees is definitely adding some drama this year," said Jeff Brindle, executive director of ELEC. The last time Assembly races topped the ballot was 1999.

The Carpenters Fund for Growth and Progress chipped in $300,000 to General Majority PAC.

General Majority's president is Susan McCue, a former chief of staff to U.S. Sen. Harry Reid of Nevada, the Democratic leader in the Senate.

Reid held a fund-raiser last year in Cherry Hill for Donald Norcross, who was elected in November to Congress representing the First District.

Norcross' brother George, the hospital and insurance executive who wields considerable influence in state politics, helped raise money for General Majority PAC in 2013, when the group was known as the Fund for Jobs, Growth and Security.

Democrats control both houses in Trenton and are unlikely to lose their majority in the Assembly.