Latvia still is viewed as the most corrupt Baltic state, is seen as the second-most corrupt in the expanded European Union, but nonetheless has improved since last year, according to the latest Corruption Perception Index by the Berlin-based Transparency International.

Latvia ranked 51st on the list released Oct. 18, an improvement from last year’s ranking of 57th. The nation shared the spot with the Central American countries of Costa Rica and El Salvador and with the Indian Ocean country of Mauritius.

The Corruption Perception Index is based on polls of business people, academics and country analysts. A total of 159 countries are included in the index, which measures opinion about the level of corruption and is based on a 10-point scale.

Latvia’s score continues to improve, climbing from 3.8 in 2003, to 4.0 last year, to 4.2 this year.

But Transparency International, as well as its Rīga-based affiliate Delna, warned that scores below 5 indicate “serious levels of corruption.”

Among the three Baltic republics, Estonia climbed four spots to a ranking of 27th with a score of 6.7, while Lithuania maintained a ranking of 44th with a score of 4.8. Transparency International singled out Estonia as among those countries where wealth is not a prerequisite for controlling corruption.

Among European Union members, only Poland scored lower than Latvia. Poland ranked 70th with a score of 3.4.

Iceland this year edged out Finland for the top spot on the index, scoring 9.7. Finland and New Zealand shared the No. 2 slot, scoring 9.6. The United States maintained its 17th place ranking, but Russia sank to 126th, sharing the spot with Albania, Niger and Sierra Leone. Last year Russia ranked 90th.