Iceland has overtaken Norway as the world's most desirable country to live in，according to according to the latest UN index on human development published on Tuesday that again puts AIDS-afflicted sub-Saharan African states at the bottom.
　　Iceland，Norway，Australia，Canada and Ireland dominate the top places but the United States slipping to 12th place from eighth last year in the UN Human Development Index.
　　But the index finds that all 22 countries falling into its "low human development" category are in sub-Saharan Africa， with Sierra Leone last.
　　In 10 of these countries， two children in five will not reach the age of 40，said the compilers at the UN Development Program. Last year's report said HIV/AIDS had had a "catastrophic effect" on life expectancy in the region.
　　The index ranks 175 UN member countries plus Hong Kong and the Palestinian territories. It does not include 17 countries， including Iraq， Afghanistan and Somalia， because of inadequate data.
　　Norway had held top spot for six years but was edged into second place by Iceland this year because of new life expectancy estimates and updated figures for gross domestic product， or GDP， the report said.
　　The United States scores high on real per capita GDP，which at $41，890 is second only to that of Luxembourg （$60，228），but less well on life expectancy —— joint last in the top 26 countries，along with Denmark and South Korea， at 77.9 years.
　　Japanese have the longest life expectancy —— 82.3 years —— and Zambians the lowest， at 40.5.
　　The report said most countries had seen their human development index rise over the last 30 years，but in 16 it was lower than in 1990，and in three —— the Democratic Republic of Congo，Zambia and Zimbabwe —— lower than in 1975.
　　Per capita GDP is 45 times higher in Iceland than in Sierra Leone.
　　The United Nations has published its human development index every year since 1990.