Least Developed Countries. The world's poorest countries. Since 1971, the UN General Assembly has recognized LDCs as a category of states that are highly disadvantaged in their development process for structural, historical and geographical reasons. The three criteria used for classifying a LDC include per capita income, human resources and economic vulnerability. Countries may "graduate" out of the LDC classification when indicators exceed these criteria. Currently 48 countries have been classified as LDCs, and only four countries have graduated to developing country status since its initiation. The LDCs have become increasingly active in UNFCCC negotiations, often working together to defend their common interests, e.g. regarding vulnerability and adaptation to climate change.