My count is nine:

1. James Monroe - shot in the shoulder during the American Revolution (Christmas Day 1776 at the Battle of Trenton)

2. Andrew Jackson - shot at least twice before his presidency: once by Charles Dickinson in a duel in 1806 (Jackson let Dickinson fire first, then killed him); and in 1813 by future Senator and political ally Thomas Hart Benton, who was angry over how Jackson acted as a second at a duel involving Benton's brother

3. Abraham Lincoln - assassinated 1865

4. Rutherford B. Hays - shot during the Civil War, once in the arm (1862) and once in the shoulder (1864); a third spent round struck his head but did not cause a serious wound (also 1864)

5. James Garfield - assassinated 1881

6. William McKinley - assassinated 1901

7. Teddy Roosevelt - shot in the chest while campaigning for a third term in 1912; he decided it wasn't a serious wound and proceeded with his 90-minute speech

8. JFK - assassinated 1963

9. Ronald Reagan - survived an assassination attempt in 1981, famously joking to his wife, "I forgot to duck," and to the doctors as he was wheeled into surgery, "I hope you're all Republicans." His surgeon replied, "Today, Mr. President, we are all Republicans."

I'd love to hear if I missed any.