Noteworthy, Poland witnesses considerable improvement of the corruption perception index (CPI) to 4.6pts (on a 0 to 10 scale where 0 indicates highly corrupt state and 10 highly clean) this year from 4.2pts in 2007. The survey included 180 countries with top flight consisting of Denmark , Sweden and New Zealand (all with CPI of 9.3pts), while worst-performers being Somalia (1.0), Myanmar (1.3) and Iraq (1.3). Although TI stresses that comparisons should be made only over longer periods of time, it did list Poland among the 18 countries whose scores improved the most from 2007 to 2008.
The survey ranks countries in terms of the degree to which corruption is perceived to exist among public officials and politicians. It is a composite index calculated using data from 13 sources originated from 11 independent institutions. All sources (dated 2007 and 2008) measure the overall extent of corruption (frequency and/or size of bribes) in the public and political sectors and all sources provide a ranking of countries, i.e., include an assessment of multiple countries.