Washington (CNN) Republican presidential candidate Jeb Bush is worth as much as $22 million, his campaign said Tuesday.

The former Florida governor released 33 years of tax returns -- the most ever revealed by a presidential candidate -- that showed he paid an average effective tax rate of 36%. His net worth is between $19 million and $22 million, aides said.

Bush's finances improved dramatically in the years after he left the governors mansion, thanks to big paychecks from speeches and consulting. After his net worth declined during his eight years in office, Bush's income exploded in 2007 -- to nearly $2.3 million or about 772% more than he earned during his final year as governor.

And his income only continued to grow. In 2013, the latest year available, Bush brought in $7.4 million. All told, Bush earned about $28.5 million between 2007 and 2013. He gave almost $750,000 to charity during that time.

Politicians often release tax returns -- opening their personal finances to public consumption -- to promote a sense of transparency surrounding their campaign. But the documents can also create political headaches. Former Republican presidential candidate Mitt Romney's tax returns in 2012 reinforced the idea that most of his earnings came in the form of lightly-taxed investment income. Bush's campaign emphasized that most of his money over the course of three decades was ordinary income, such as wages. But his returns could revive questions about his work in the financial sector.

For instance, Bush made an average of about $2 million annually during the six years he was a paid advisor at the financial services company Barclays.

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During his two years as an advisor to the now-defunct investment bank Lehman Brothers, he averaged about $1.3 million in compensation, aides said. In a lengthy narrative of his business career posted on his campaign website, Bush does not mention the bank, which collapsed during the 2008 financial crisis.

Bush has taken fire for working with banks during the financial meltdown and supporting the 2008 government bank bailout.

The former governor also cashed in on the speaking circuit after leaving office. Between 2007 and 2015, Bush made nearly $10 million speaking to such diverse groups and companies as General Motors, Stanford University and The Fertilizer Institute.

The campaign released personal income tax returns from 1981 to 2013. The 2014 return has not been filed because Bush is still waiting to receive tax paperwork from his business partnerships, aides said.

The campaign, aides said, has also asked the Federal Election Commission to extend by 45 days the deadline to file his personal financial disclosure, a requirement of every presidential candidate.

Bush is only the second presidential candidate this cycle to release tax returns since announcing a run for the White House. Carly Fiorina released two years of tax returns earlier this month. The former Hewlett Packard chief executive, along with her husband, has a net worth of $59 million.

Bush's release of three decades of tax records comes after he released hundreds of thousands of emails from his time as Florida governor.

"I put them all out because I wanted people to have a window into my leadership style and be able to see for themselves how I handled the issues facing our state," Bush wrote on his website.

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The document releases are designed to position Bush as the most open candidate in the presidential field. They contrast Bush with Democratic frontrunner Hillary Clinton, who has come under fire for doing government business as secretary of state on a private email server. She has turned over emails she said were work related to the State Department, which was set to release 3,000 more pages of her emails on Tuesday.

In between calls for a fairer and flatter tax code, Bush took a swipe at Clinton.

"One fun fact I learned in this process: I have paid a higher tax rate than the Clintons even though I earned less income," Bush wrote.

Bush paid an average effective tax rate of 36% over three decades. Clinton's campaign estimated that her 2014 effective tax rate would be more than 30%. A Clinton spokesman noted that she released returns from 1977 to 2006 during her last run for president and plans to release additional returns.