So far, President Trump has refused to release his tax returns while in office, breaking with a 40-year tradition.

He has claimed that ongoing IRS audits prevent him from doing so, even though such audits wouldn't restrict anyone from publishing their returns. And Trump is mandated to be audited during the rest of his time in office.

White House Press Secretary Sean Spicer on Monday reiterated Trump's stance.

"It's the same thing that was discussed during the campaign trail -- the president is under audit. It's a routine one that continues," Spicer said. "Nothing has changed."

Related: The president always gets audited (and the veep too)

But Trump's public statements about his returns have shifted subtly over the years.

At first, Trump was open about wanting to release his returns. He began citing the ongoing audit as a reason not to release them in early 2016.

Here's a selection of remarks Trump has made:

MAY 20, 2014:

More than a year before he announced his presidential campaign, Trump told an Irish television station that he would "absolutely" release his tax returns if he entered the race.

"If I decide to run for office, I'll produce my tax returns, absolutely," he said. "And I would love to do that."

FEBRUARY 25, 2015:

Trump told radio host Hugh Hewitt that he would "certainly show tax returns if it was necessary."

OCTOBER 4, 2015:

Trump said in an interview with ABC's George Stephanopoulos that he was considering releasing his tax returns.

"I'm thinking about maybe when we find out the true story on Hillary's emails," he said of Democratic presidential candidate Hillary Clinton.

JANUARY 24, 2016:

Trump told NBC's Chuck Todd that he had "very big returns."

Asked if he would release them publicly, Trump said, "we're working on that now."

"I have very big returns, as you know, and I have everything all approved and very beautiful and we'll be working that over in the next period of time, Chuck," Trump said. "Absolutely."

FEBRUARY 11, 2016:

Trump appeared again on Hewitt's radio program and said of his returns, "we'll get them out at some point, probably."

FEBRUARY 24, 2016:

Trump told CNN's Anderson Cooper that he has a "very complex system of taxes."

"We'll make a determination over the next couple of months," he said. "It's very complicated."

FEBRUARY 25, 2016:

Trump tweeted that he's already filed public financial disclosure forms that are "great." He said that tax returns "have 0 to do w/ someone's net worth."

The disclosure forms do give wide estimates of asset value. But tax returns would reveal much more. Even the top two pages of his 1040 and Schedule A, for example, would say how much taxable income he made, how much he paid in taxes, his charitable contributions and whether he paid tax to any foreign governments.

Just for your info, tax returns have 0 to do w/ someone's net worth. I have already filed my financial statements w/ FEC. They are great! — Donald J. Trump (@realDonaldTrump) February 25, 2016

During a CNN-Telemundo debate later that day, Trump said he wanted to release his tax returns, but could not while he's under audit.

"I've had it for years. I get audited. And obviously if I'm being audited, I'm not going to release a return," he said. "As soon as the audit is done, I love it."

FEBRUARY 27, 2016:

Trump revisits the audit argument on Twitter.

"Tax experts throughout the media agree that no sane person would give their tax returns during an audit," he said. "After the audit, no problem!"

Tax experts throughout the media agree that no sane person would give their tax returns during an audit. After the audit, no problem! — Donald J. Trump (@realDonaldTrump) February 27, 2016

MAY 11, 2016:

Trump tells the Associated Press that his taxes are under "routine audit" and he will release them when the audit is done.

"I would release my tax returns when audit is complete, not after election!" he tweeted about the interview.

In interview I told @AP that my taxes are under routine audit and I would release my tax returns when audit is complete, not after election! — Donald J. Trump (@realDonaldTrump) May 11, 2016

SEPTEMBER 27, 2016:

Trump says during the first presidential debate that his taxes will be released once an audit is finished.

"I don't mind releasing. I'm under a routine audit, and it will be released. As soon as the audit's finished, it will be released," he said.

OCTOBER 4, 2016:

Mike Pence says during a vice presidential debate with Democratic candidate Tim Kaine that Trump has not "broken his promise" about releasing tax returns.

"Look, Donald Trump has filed over 100 pages of financial disclosure, which is what the law requires," Pence said. He added that trump is "going to release his tax returns when the audit is over."

JANUARY 22, 2017:

White House senior adviser Kellyanne Conway said on ABC's "This Week" that "the White House response is that he's not going to release his tax returns."

She added: "We litigated this all through the election. People didn't care."

JANUARY 23, 2017:

Conway clarifies her comments with a tweet: "On taxes, answers (& repeated questions) are same from campaign: POTUS is under audit and will not release until that is completed."

On taxes, answers (& repeated questions) are same from campaign: POTUS is under audit and will not release until that is completed. #nonews — Kellyanne Conway (@KellyannePolls) January 23, 2017

APRIL 16, 2017:

A day after protestors called on Trump to release his tax returns, the president derided the demonstrators on Twitter.

"I did what was an almost an impossible thing to do for a Republican-easily won the Electoral College!" he tweeted. "Now Tax Returns are brought up again?"

I did what was an almost an impossible thing to do for a Republican-easily won the Electoral College! Now Tax Returns are brought up again? — Donald J. Trump (@realDonaldTrump) April 16, 2017

APRIL 17, 2017:

Spicer, the White House press secretary, says Trump's tax returns are still under audit.

"It's the same thing that was discussed during the campaign trail, the president is under audit. It's a routine one that continues," he said.

Asked in a later exchange if we can assume Trump will never release his returns, Spicer said he would "get back to you on that."

--CNNMoney's Jeanne Sahadi contributed to this story.