WASHINGTON – President Donald Trump's U.S. businesses have received at least $15.1 million in revenue from political groups and federal agencies since 2015, according to a report to be released Monday.

The money went to Trump's airplanes, hotels, golf courses and even a bottled water company during the presidential campaign and the first 15 months of his presidency, according to a compilation of spending records prepared by Public Citizen and obtained by McClatchy.

But it was Trump's campaign itself that spent the most by far — about 90 percent, or $13.4 million.

It also includes more than $717,000 from the Republican National Committee; nearly $595,000 from Trump Victory, the joint fundraising committee set up by the RNC and Trump's campaign; and $9,000 from the National Republican Senate Committee.

Political action committee American First Action, dedicated to electing federal candidates who support Trump's agenda, spent $33,000 and Great America Committee, Vice President Mike Pence's group, spent $24,000.

Campaigns and committees supporting Republican House members Bill Shuster of Pennsylvania, Jodey Arrington of Texas, Tom MacArthur of New Jersey and Dana Rohrabacher of California also spent money on Trump businesses.

In comparison, in 2013 and 2014, political spending at his properties was less than $20,000.

The total is likely to be much more. There is no single place to find out how much the administration is spending at Trump businesses, though federal agencies have started to disclose some information in response to public record requests. Public Citizen analyzed Federal Election Commission data and federal agency records obtained from Freedom of Information Act requests by Public Citizen and Property of the People, a group of legal experts and activists.

Before he was sworn into office, Trump eschewed calls to fully separate from his business interests.

Instead he put his holdings in a trust designed to hold assets for his "exclusive benefit," which he can receive at any time without the public's knowledge. He also retains the authority to revoke the trust.

Trump launched his campaign at one of his buildings, Trump Tower in New York, where his campaign leased space. Campaign events offered Trump-branded water and wine. The campaign and Secret Service paid Tag Air Inc. for use of Trump's Boeing 757 airplane, customized with gold-plated bathroom faucets and seat belts.

Since his inauguration, Trump has visited one of his properties, usually in Florida, New Jersey or Virginia, on 138 days, according to the White House. Those visits have led to government spending.

Recipients include Trump Tower Commercial LLC, Trump International Hotel in Washington, Mar-a-Lago club in West Palm Beach, Fla., Trump National Doral Miami, Trump International Hotel Las Vegas, Trump Restaurants LLC, the Trump Corp., Trump Payroll Corp. and Trump Plaza LLC.

Rep. Jackie Speier, D-Calif., is expected to introduce a bill that would prohibit government spending at properties owned by officeholders if the money provides a profit to the officeholders.

"Trump has raised the art of the self-deal to unprecedented heights, enriching himself at the expense of taxpayers," said Craig Holman, lobbyist for Public Citizen. "This requires a legislative response."