The unique fraternity of presidents fascinates people from all walks of life. These men are scrutinized for the power that they wield and for their actions within their personal lives. Collectively, they have had thousands of books written about them and their actions. Before looking at each of the presidents individually, let's take a look at some of the facts surrounding the group as a whole.

Age

Most of the presidents were elected for the first time in their fifties. The youngest president to serve in office was Theodore Roosevelt, who was forty-two when he took over after William McKinley's assassination. The youngest elected president was John F. Kennedy at the age of forty-three. Ronald Reagan was the oldest president — he was elected at age sixty-nine and served until he was seventy-eight.

Religion

The two most common religions practiced by presidents are Episcopalian and Presbyterian. There have been two Quakers and one Roman Catholic president: Herbert Hoover and Richard Nixon, and John F. Kennedy, respectively. Here are the top six most common religious groups with percentages:

• Episcopalian — 31 percent

• Presbyterian — 24 percent

• Methodist — 12 percent

• Baptist — 9 percent

• Unitarian — 9 percent

• Disciples of Christ — 7 percent

Military Service

Thirty-one presidents (74 percent) have served in the military. The highest ranking military positions held were by George Washington as the general and commander-in-chief of the Continental Army; Dwight Eisenhower as five-star general of the Allied Forces during World War II; and Ulysses S. Grant as four-star general of the army during the Civil War. Six of the presidents served in the U.S. Navy. The presidents who saw no military service were:

• John Adams

• John Quincy Adams

• Martin Van Buren

• Grover Cleveland

• William Howard Taft

• Woodrow Wilson

• Warren G. Harding

• Calvin Coolidge

• Herbert Hoover

• Franklin D. Roosevelt

• William Jefferson Clinton

While military service is not a prerequisite for the presidency, it is seen as important due to the role the president will be assuming as commander-in-chief of the U.S. military.

Term of Office

There have been only twelve presidents in the history of the office who were elected to two terms. In the beginning, there was no official limit to the number of terms that a president could serve. George Washington set a precedent by leaving office after his second term that was upheld until Franklin D. Roosevelt. Roosevelt ran for and was elected to four terms. He died in office during his fourth stint and Harry S. Truman took over as president. The twenty-second amendment was passed to stop this from ever happening again. According to this amendment, a president is limited to two terms or ten years. A presidential term lasts only four years, but this rule allows for a person to succeed to the presidency for two years before actually running in the general elections.

If a president is unable to continue their duties due to death, resignation, or impeachment, then the Constitution states that the vice president will take over as president. In 1792, an act was passed to set up an order of succession in case the vice president isn't able to take over. However, it was not until the twenty-fifth amendment in 1967 that the order was constitutionally set or that any provision was made for filling the vice presidential office if a succession should occur. Following is the order of succession:

• Vice President

• Speaker of the House

• President Pro Tempore of the Senate

• Secretary of State

• Secretary of the Treasury

• Secretary of Defense

• Attorney General

• Secretary of the Interior

• Secretary of Agriculture

• Secretary of Commerce

• Secretary of Labor

• Secretary of Health and Human Services

• Secretary of Housing and Urban Development

• Secretary of Transportation

• Secretary of Energy

• Secretary of Education

• Secretary of Veteran's Affairs

• Secretary of Homeland Security

Future additions to the order of succession are made based on the order in which cabinet positions are created. Therefore, if a new cabinet post is created after homeland security, that office will become last in the line of presidential succession.

Education

Education has varied from president to president. Six presidents never attended college or studied for an advanced degree at all. They were:

• Andrew Jackson

• Zachary Taylor

• Millard Fillmore

• Abraham Lincoln (though he did become a lawyer by studying on his own and passing the bar)

• Andrew Johnson

• Grover Cleveland

The college from which the most presidents graduated was Harvard with five. Only one president, Woodrow Wilson, had a doctorate. William Henry Harrison attended medical school but dropped out before getting his medical degree. Bill Clinton was a Rhodes Scholar at Oxford University. The most common occupation before becoming president was lawyer. In fact, twenty-five of the forty-two individuals who became president practiced law.

Political Parties and Electoral Votes

The Republican party began around the time of Abraham Lincoln's first election as president. Including Lincoln, eighteen presidents have hailed from the Republican party. That means that 42 percent overall — or 64 percent of the possible elections in which they participated — have been won by Republicans. The political parties represented by the presidents over time are in order of percentage that won the vote:

• Republican — 42 percent

• Democratic — 33 percent

• Whig — 9.5 percent

• Democratic-Republican — 9.5 percent

• Union — 2 percent (Lincoln ran under the Union party the second time)

• Federalist — 2 percent

• No Party — 2 percent

Presidents have won by very large and very narrow margins. The president who received the highest percentage of electoral votes was George Washington. He was the only one to be elected unanimously to both terms in office. Other presidents who received more than 90 percent of the electoral vote include James Monroe, Franklin Roosevelt, Ronald Reagan, and Richard Nixon.