Assassination attempts and plots on Presidents of the United States have been numerous: more than 20 attempts to kill sitting and former presidents, as well as the Presidents-elect, are known. Four sitting presidents have been killed: Abraham Lincoln (the 16th President), James A. Garfield (the 20th President), William McKinley (the 25th President) and John F. Kennedy (the 35th President). Two presidents were injured in attempted assassinations: Theodore Roosevelt (the 26th President) and Ronald Reagan (the 40th President). With the exception of Lyndon Johnson, every president's life since John F. Kennedy has been threatened with assassination.