Sicily

The rate of Cousin marriages is in general very low in Europe, since the Western Church was preventing this. In northern Italy, the frequency of cousin marriage is less than 0.4 percent. But in the south, that rate becomes much higher. Over 4% at the tip of the italian boot an in much of Sicily. Normally, permission had to be asked to the Vatican to be allowed to marry your cousin. But because the rate is so high in these areas, the bishop could deal with it himself and grant the rights. In his great book "The Weirdest People in the Wolrd", Joseph Henrich discovers and explains all kind of correlations with high cousin marriage rates. One of them is a positive correlation with corruption and negative corruption with blood donations. The greater the rate of cousin marraige in a province, the higher the rates of corruption and Mafia activity. 

Dromos