By an Act of Congress passed in 1903, two midshipman appointments were allowed for each senator, representative, and delegate in Congress, two for the District of Columbia, and five each year at large. Currently each member of Congress and the Vice President can have five appointees attending the Naval Academy at any time. When any appointee graduates or otherwise leaves the academy, a vacancy is created. Candidates are nominated by their senator, representative, or delegate in Congress, and those appointed at large are nominated by the Vice President. The applicants do not have to know their Congressman to be nominated. Congressmen generally nominate ten people per vacancy. They can nominate people in a competitive manner, or they can have a principal nomination. In a competitive nomination, all ten applicants are reviewed by the academy, to see who is the most qualified. If the congressman appoints a principal nominee, then as long as that candidate is physically, medically, and academically found qualified by the academy, he or she will be admitted, even if there are more qualified applicants. The degree of difficulty in obtaining a nomination varies greatly according to the number of applicants in a particular state. The process of obtaining a nomination typically consists of completing an application, completing one or more essays, and obtaining one or more letters of recommendation and often requires an interview either in person or over the phone. These requirements are set by the respective senator or representative and are in addition to the USNA application.