The NBA draft is an annual event dating back to 1947 in which the thirty teams from the National Basketball Association (NBA) can draft players who are eligible and wish to join the league. These are typically college basketball players, but international players are also eligible to be drafted. College players who have finished their four-year college eligibility are automatically eligible for selection, while the underclassmen have to declare their eligibility and give up their remaining college eligibility. International players who are at least 23 years old are automatically eligible for selection, while the players younger than 22 have to declare their eligibility. Players who are not automatically eligible but have declared their eligibility are often called "early-entrants" or "early-entry candidates". The draft usually takes place at the end of June, during the NBA off-season. Since 1989, the draft has consisted of two rounds; this is much shorter than the entry drafts of the other major professional sports leagues in the United States and Canada, all of which run at least seven rounds. Sixty players are selected in each draft. No player may sign with the NBA until he has been eligible for at least one draft.