Transparency International's (TI's) latest global corruption barometer of the most and least corrupt nations shows that Liberia has dropped one point on the global scale, but ranks high in West Africa.

The only country that beats Liberia as the least corrupt in West Africa is Ghana, according to TI.

Liberia tops Nigeria, Ivory Coast, Sierra Leone and Guinea in the sub-region, according to TI.

In the past four years, according to the report, Liberia made progress, with scores of 2.4 points in 2008, 3.1 points in 2009, 3.3 points in 2010 but dropped by 0.1 points to 3.2 points in 2011.

The country now ranks 91 along with Trinidad and Tobago, Bosnia and Herzegovina and Zambia out of 164 rankings.

Nigeria ranked 143, with scores of 2.4 in 2011, 2.4 in 2010, 2.5 in 2009 and 2.7 in 2008, while the Ivory Coast ranked 154 with scores of 2.2 points in 2011, 2.2 points in 2010, 2.1 points in 2009 and 2 points in 2008. Guinea ranked 164 with scores of 2.1 points in 2011, 2 points in 2010,

1.8 points in 2009 and 1.6 points in 2008 while Sierra Leone ranked 134 with scores 2.5 points in 2011, 2.4 points in 2010, 2.2 points in 2009 and

1.9 points in 2008.

This year, two thirds of all countries covered by the index were given scores less than 5 - which means they are considered significantly corrupt.

The CPI scores countries on a scale of zero to 10, with zero indicating high levels of corruption and 10, low levels. And the most corrupt places in the world are not the most surprising.

Unstable governments, often with a legacy of conflict, continue to dominate the bottom rungs of the CPI. Afghanistan and Myanmar share second to last place with a score of 1.5, with Somalia and North Korea - measured for the first time - coming in last with a score of 1.

The report coincides with the observance of today's World Anti-Corruption Day which also reveal that 80% or 5.6 billion human beings worldwide live under corrupt governments.

Transparency International based its tables on the populations of the assessed countries in 2011 CPI and came to the horrific realization that Planet Earth remains a highly inequitable place.

The report is not a verdict on the levels of corruption of societies - it is an assessment of administrative and political corruption only. The report is based on "perceptions", but it is far more accurate and scientific than what that vague term would normally suggest.

Corruption is illegal and rather difficult to assess on the basis of hard empirical data. The methodology used in compiling comparable country data for the report involves capturing perceptions of those in a position to offer expert assessments of public sector corruption in a given country.

The world's most peaceful countries score the best. In the 2011 CPI, New Zealand is top with a score of 9.5, followed by Denmark, Finland, Sweden and Singapore, the report notes.

Wealth seems no easy antidote to corruption: some relatively rich countries, including Russia, fall at the bottom of the global league table. Meanwhile, some of the world's poorer states do comparatively well: Botswana, Bhutan, Cape Verde, and Rwanda all appear among the 50 "cleanest" countries.

The Index, which is closely watched by investors, economists, and civil society campaigners, is based on expert assessments and data from 17 surveys from 13 independent institutions, covering issues such as access to information, bribery of public officials, kickbacks in public procurement, and the enforcement of anti-corruption laws. While critics note that measuring perceptions of corruption is not the same as measuring corruption itself, the latter is almost impossible to do - as the corrupt are usually keen to cover up their tracks, hard data on graft and bribery is notoriously difficult to come by, according to the report.