1955
1945
2002
1965.
1946
1985
November 12, 1956
Italy join the Six Nations Championship in 2000
The Lao PDR joined the United Nations on 14 December 1955.
Original Answer: Because they are decades away. Improved: The United Nations are not a country. They couldn't have "joined" the League of Nations. The League of Nations was the predecessor of the United Nations - the League of Nations failed, and so, many years later in 1942 (I believe it was that year) they founded the United Nations as an improved "League of Nations."
in 1980
September 18, 1962
Madagascar joined the United Nations on September 20, 1960. This means that the country has been a member for over 50 years (2013, it has been a member for 53 years).