By Douglas A. McIntyre, Michael B. Sauter and Ashley C. Allen, 24/7 Wall St.

After months of speculation, GOP presidential candidate Mitt Romney recently confirmed that he is worth roughly $200 million -- give or take a million or more. In addition to being worth more than 99.9 percent of Americans, if elected president, Romney would also be wealthier than any president except one.

While the other Republican candidates are also millionaires, their wealth does not come close to that of Romney’s. Still, judging from the net worth of all presidential nominees, politicians need to be wealthy to run for high office.

The others made their money more directly from their politics before becoming a presidential candidate. Libertarian candidate Ron Paul, worth between $2.5 and $5 million, has published a number of best-selling books over the past few years, each of which explores his political ideology. Former House Speaker Newt Gingrich became a consultant and political analyst after he resigned from office. According to estimates, he has earned at least $6.5 and as much as $31 million. Rick Santorum, who worked as a consultant and contributor to Fox News, is worth more than $1 million.

24/7 Wall St. examined the finances of all 43 presidents. Unlike today’s candidates, the net worth of the presidents varies widely. George Washington was worth over half a billion in today’s dollars, while other presidents went bankrupt.

The fortunes of America’s presidents are tied to the economy of their time. As the focus of the economy changed, so has the way the presidents made their money.

It’s not surprising then to find the first few presidents -- from Washington’s election to about 75 years later -- as large landowners. They generally made money from land, crops and commodity speculation. Of course, this left them highly vulnerable to poor crop yields, and they could lose most or all of their properties because of a few bad years. Similarly, they could lose all of their money through land speculation -- leveraging the value of one piece of land to buy additional property.

By 1850, the financial history of the presidency entered a new era. Beginning with Millard Fillmore, most presidents were lawyers who spent years in public service. They rarely amassed large fortunes and their incomes were often almost entirely from their salaries. These American presidents were distinctly middle class and often retired without the means to support themselves anywhere close to the presidential lifestyle. Buchanan, Lincoln, Johnson, Grant, Hayes and Garfield had modest net worth when they died.

At the end of the 19th century and the beginning of the 20th, there was another significant change to the economy. Large, professionally organized corporations in the oil, mining, financial and railroad sectors allowed individuals to amass large fortunes. The Kennedys were wealthy because of the financial empire built by Joseph Kennedy. Herbert Hoover made millions of dollars as the owner of mining companies. Indeed, since the early 20th century, the fortunes of many presidents, including Theodore Roosevelt, Franklin D. Roosevelt, John F. Kennedy and both of the Bushes, were driven by inherited wealth.

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The net worth figures for the 10 wealthiest presidents are in 2010 dollars. Because a number of presidents, particularly in the early 19th century, made and lost huge fortunes in a matter of a few years, the net worth for each president is for the peak time.

In the case of each president, we have taken into account hard assets such as land, estimated lifetime savings based on work history, inheritance, homes and money paid for services, which includes anything from salary as Collector of Customs at the Port of New York to membership on Fortune 500 companies’ boards. The net worth includes royalties on books, as well as ownership of companies and yields from family estates.

This is 24/7 Wall St.'s list of the richest U.S. presidents.

10. John Fitzgerald Kennedy

Net worth: $1 billion (never inherited his father’s fortune)

In office: 1961 - 1963

35th president

Born into great wealth, Kennedy’s wife was an oil heiress. His father was one of the wealthiest men in America, as well as was the first chairman of the SEC. Almost all of JFK’s income and property came from a trust shared with other family members.

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9. William Jefferson Clinton

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Net worth: $38 million

In office: 1993 - 2001

42nd president

Unlike other presidents, Clinton did not inherit any wealth and gained little net worth during 20 plus years of public service. After his time in the White House, however, he earned a substantial income as an author and public speaker. Clinton received a large advance for his autobiography. His wife, the current Secretary of State, also has earned money as an author.

8. Franklin Delano Roosevelt

Net worth: $60 million

In office: 1933 - 1945

32nd president

Roosevelt’s wealth came through inheritance and marriage. He owned the 800-acre Springwood estate, as well as properties in Georgia, Maine and New York. In 1919, his mother had to bail him out of financial difficulty. He spent most of his adult life in public service. Before he was president, Roosevelt was appointed assistant secretary of the Navy by President Wilson.

7. Herbert Clark Hoover

Net worth: $75 million

In office: 1929 - 1933

31st president

An orphan, Hoover was raised by his uncle, a doctor. He made a fortune as a mining company executive. He had a very large salary for 17 years and had extensive holdings in mining companies. Hoover donated his presidential salary to charity. He also owned “Hoover House” in Monterey, Calif.

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6. Lyndon Baines Johnson

Net worth: $98 million

In office: 1963 - 1969

36th president

Johnson’s father lost all of the family’s money when LBJ was a boy. Over time, he accumulated 1,500 acres in Blanco County, Tex., which included his home, called the “Texas White House.” He and his wife owned a radio and television station in Austin, Tex., and had a variety of other moderate holdings, including livestock and private aircraft.

5. James Madison

Net worth: $101 million

In office: 1809 - 1817

4th president

Madison was the largest landowner in Orange County, Va. His land holding consisted of 5,000 acres and the Montpelier estate. He made significant wealth as Secretary of State and president. Madison lost money at the end of his life due to the steady financial collapse of his plantation.

4. Andrew Jackson

Net worth: $119 million

In office: 1829 - 1837

7th president

While he was considered to be in touch with the average middle class American, Jackson quietly became one of the wealthiest presidents of the 1800s. “Old Hickory” married into wealth and made money in the military. His homestead, The Hermitage, included 1,050 acres of prime real estate. Over the course of his life, he owned as many as 300 slaves. Jackson entered considerable debt later in life.

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3. Theodore Roosevelt

Net worth: $125 million

In office: 1901 - 1909

26th president

Born to a prominent and wealthy family, Roosevelt received a sizable trust fund. He lost most of his money on a ranching venture in the Dakotas and had to work as an author to pay bills. Roosevelt spent most of his adult years in public service. His 235-acre estate, Sagamore Hill, sits on some of the most valuable real estate on Long Island.

2. Thomas Jefferson

Net worth: $212 million

In office: 1801 - 1809

3rd president

Jefferson was left 3,000 acres and several dozen slaves by his father. Monticello, his home on a 5,000-acre plantation in Virginia, was one of the architectural wonders of its time. He made considerable money in various political positions before becoming president, but was mired in debt towards the end of his life.

1. George Washington

Net worth: $525 million

In office: 1789 - 1797

1st president

His Virginia plantation, Mount Vernon, consisted of five separate farms on 8,000 acres of prime farmland, run by more than 300 slaves. His wife, Martha Washington, inherited significant property from her father. Washington made well more than subsequent presidents: his salary was 2 percent of the total U.S. budget in 1789.

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