Bulgaria is ranked at number 55 out of 184 countries by quality of life in the annual human development index (HDI) published by the United Nations Development Programme (UNDP). The country does even better in the version adjusted for social inequality, moving up three positions to 52.

In the past two years, Bulgaria has climbed in the overall ranking, going from number 61 in 2009 to 58 in 2010.  

Both HDI versions have the same leader as in 2010 – Norway. This makes it the ninth consecutive year in which the country has topped the chart. Australia comes second, also in both HDI editions. The Netherlands is placed at number three in the overall rankings and number four in the adjusted index, while the USA ranks fourth overall but has dropped to number 23 in the social equality chart.

The HDI has been compiled by the UNDP for the past 21 years and takes into account economic prosperity (income being the determinant), level of education and life expectancy. The adjusted index, which reflects inequalities in these areas of human development, was introduced in 2010 and the UN intends to incorporate it into its main index, according to Reuters.  

A number of other rich countries besides the USA have been ranked significantly lower in the equality index compared to their positions in the overall chart. Canada slides to number 12 from six previously, while South Korea has dropped from 15 to 28.

Some countries, on the other hand, do better in the social equality stakes. Sweden, for example, is placed at number 10 in the overall rankings but occupies the third position in the equality chart, while the respective numbers for Denmark are 16 and eight.

Languishing at the bottom of the table is the Democratic Republic of Congo, which has been torn apart by wars for more than a decade. It ranks at number 187 in the overall index and at 134 in the adjusted version. The positions above Congo are occupied by Niger, Burundi, Mozambique and the Chad.

The countries in the chart are divided into five groups. There are four groups according to quality of life, the degrees assigned to it being very high, high, medium and low. There is also a group labelled as "other" and including North Korea, the Marshall Islands, Monaco, Nauru, San Marino, Somalia and Tuvalu. Bulgaria (55/52) is found at the upper end of the group featuring countries with high quality of life. It is in the company of Romania (50/49), Cuba (51/51), Montenegro (54/47) and Saudi Arabia ( 56/56), among others. In that same group but ranked lower is Russia (66/59). China (101/102) falls into the group of countries with average quality of life.