Oil and gas executives usually give their money to Republicans, but this presidential election it's Democrat Hillary Clinton Hillary Diane Rodham ClintonJoe Biden looks to expand election battleground into Trump country Biden leads Trump by 12 points among Catholic voters: poll The Hill's Campaign Report: Biden goes on offense MORE who's getting most of their cash, according to a new Wall Street Journal report.

Oil and gas executives and employees have given Clinton's campaign and joint fundraising committee nearly double what they have donated to the GOP nominee,

While Clinton has raised tens of millions more than Trump across all industries, the oil and gas sector's outsized contributions stand out.

People working for oil and natural gas companies donated $525,000 to Clinton's campaign, compared to $149,000 to Trump’s, through July 30, according to figures provided to the Journal by the non-partisan Center for Responsive Politics.

The Journal also reported that oil and gas executives and employees have donated another $650,000 to Clinton's joint fundraising account with the Democratic National Committee and a number of state parties, compared with $470,000 to Trump's equivalent joint fundraising account.

But the oil and gas industry has been a major backer of Republican candidates for decades.

Since 1989, about 60 percent of the $500 million the industry spent on U.S. elections has gone to the GOP and its candidates, according to the CRP data provided to the Journal.

And so far in the 2016 cycle, oil and gas executives and employees have spent some 90 percent of their $71 million in campaign contributions on Republicans — those not named Trump — according to the Journal.

Clinton is set to out-raise Trump on a scale unseen in the modern era.

She raised more than $320 million as of the end of July, and that's not counting the more than $140 million her campaign said it jointly raised with the DNC and state parties in the month of August.

Nor does it count the more than $150 million in advertising already reserved by a powerful outside group, Priorities USA, which is supporting Clinton's candidacy.

Trump, by contrast, has been running a threadbare campaign with about a tenth of the staff of Clinton and has only recently begun buying TV ads.

The New York billionaire mostly self-funded his primary campaign, using about $50 million from his own pocket.

At the end of July, Trump's campaign reported raising a total of $128 million in the cycle to date. That's less than half of Clinton's haul.