Burundi is one of the world's poorest countries, owing in part to its landlocked geography, poor legal system, lack of economic freedom, lack of access to education and the proliferation of HIV/AIDS. Approximately 80% of Burundi's population lives in poverty. Famines and food shortages have occurred throughout Burundi, most notably in the 20th century, and according to the World Food Programme, 56.8% of children under age five suffer from chronic malnutrition. Burundi's export earnings – and its ability to pay for imports – rests primarily on weather conditions and international coffee and tea prices.Graphical depiction of Burundi's product exports in 28 colour-coded categories in 2009.