Norway has retained its status as the world's most desirable country to live in, according to UN figures

The sub-Saharan African states affected by war and HIV/Aids were ranked as the least attractive places.

Information collected prior to the global economic crisis showed people in Norway, Australia and Iceland had the best living standards. The UK was in 21st place.

Niger, Afghanistan and Sierra Leone scored worst in terms of human development.

The United Nations Development Programme (UNDP) index was compiled using 2007 data on GDP per capita, education, and life expectancy.

It showed marked differences between the developed and developing world.

"Despite significant improvements over time, progress has been uneven," UNDP said in a statement.

"Many countries have experienced setbacks over recent decades, in the face of economic downturns, conflict-related crises and the HIV/AIDS epidemic, and this was even before the impact of the global economic crisis was felt."

Life expectancy in Niger was 50, about 30 years shorter than Norway, according to the index. For every dollar earned per person in Niger, $85 was earned in Norway.

Half the people in the poorest 24 countries were illiterate, compared to 20% in nations classed as having medium levels of human development, the index showed.

Japanese people lived longer than others, to 82.7 years on average, with life expectancy in war-ravaged Afghanistan just 43.6 years.

Liechtenstein has the highest gross domestic product per capita at $85,383 in a tiny principality that is home to 35,000 people, 15 banks and more than 100 wealth management companies.

People were poorest in the Democratic Republic of Congo, where average income per person was $298 per year.