Romanian corruption map

The dark blue counties represent highly corrupted counties, the medium dark blue represents medium corrupted counties and the light blue colored counties represent low corrupted counties. The ratio was calculated by dividing the maximum reported bribes in the county in EUR to the population of the county in thousands of people. Dark blue equals a ration above 1.5, medium blue represents a ration between 1 and 1.5, and light blue represents a ration below 1. Data comes from official data regarding population and bribes are collected from http://www.piatadespaga.ro. Map was made with MapWindows GIS 4.8 and data can be sent by request. I can see some interesting patterns but I do not know how to explain them. The most corrupted counties seem clustered together for some reason.
coruptie