WASHINGTON -- Republican presidential candidates Marco Rubio and Ted Cruz on Saturday released summary pages of their tax returns from the past several years, an effort to raise pressure on businessman Donald Trump to do the same.

Rubio's filings revealed him to be a presidential candidate with a senator's steady annual income of $176,000 who reaped profits from book deals.

During his first four years in the Senate, Rubio and his wife, Jeanette, together earned an average of $531,000 a year. Jeanette Rubio has been a paid adviser to the charitable foundation of Norman Braman, a Florida auto dealer and major Rubio donor.

Since winning election to an office in Washington, Rubio's income has ranged from $276,059 to $938,963, and he has paid between $46,500 and $254,894 in federal income tax. A comparison with personal Senate financial disclosures shows most of the income came from a business that collected royalties on two books: Rubio's memoir, An American Son, and a pre-campaign tract, American Dreams.

In 2012, his effective tax rate topped out at a little more than 31 percent. But by 2014 -- the last year for which a return summary is available -- the family's income dropped to $335,963, an amount on which the Rubios paid a 24 percent tax rate. Rubio's earnings that year were increased by cashing out $68,241 from his retirement savings.

The tax documents Rubio has released are not complete tax filings, as Mitt Romney provided in 2012 and Hillary Clinton produced last year. Instead, Rubio released the first two pages of his 1040 form, which summarizes the details of his income and taxes.

Like Rubio, Cruz on Saturday released the first two pages of each return over a four-year period. The filings showed that Cruz and his wife, Heidi, paid $1.5 million in federal income taxes between 2011 and 2014 on adjusted gross income totaling more than $5 million. It's not clear how much of the income can be attributed to Heidi Cruz, who works as an investment manager for Goldman Sachs.

For 2011, the Cruzes reported earning $1.7 million in adjusted gross income. In 2012, the year Ted Cruz was elected as a senator from Texas, the couple reported $1.1 million. The couple made $970,193 in 2013 and $1.2 million in 2014. Their average federal tax rate over the four-year period was 29.9 percent.

In each return filed over the period, Cruz and his wife indicated that they had sought extended time to file and had prepaid certain amounts. In 2014, the couple indicated that they paid $166,887 alongside their request for a filing extension. For 2013, the figure was $85,000; in both 2012 and 2011, it was $45,000.

Cruz said he was releasing only partial information because that's what Rubio did.

"If Marco wants to release the full thing for the recent years, I'm happy to do so as well," Cruz said. "We just did it to match what the other candidates are doing. This is a competitive race."

The release of the two candidates' tax filings came after Trump said in Thursday's GOP debate that his returns have been the subject of audits for at least a dozen consecutive years. He said he would not release them until that process concludes.

In a CNN interview after the debate, Trump said he has been targeted by the Internal Revenue Service because he's a Christian.

"We're putting these out today to put pressure on Trump and the other candidates to release theirs," said Rubio campaign spokesman Alex Conant. "To the extent there are additional questions about Marco, we won't rule out providing more information in the future."

Cruz also called on Trump to release his tax returns.

"It's possible Trump has been a significant donor to left-wing organizations, such as Planned Parenthood, which would seriously undermine his claim to be pro-life," Cruz said in the statement.

Information for this article was contributed by Jeff Horwitz and Chad Day of The Associated Press; by Rosalind S. Helderman, Tom Hamburger and Katie Zezima of The Washington Post; and by Lynnley Browning of Bloomberg News.

A Section on 02/28/2016