There, it was estimated that the prevalence of PC is between 1:350,000 (0.00028%) and 1:180,000 (0.00056%).[20] However, the German population of patients with PC is not uniformly distributed across the country. Many individuals with PC herald from the Ravensberg area in North-West Germany, where a founder effect seems to be responsible for most cases.[20][34] The prevalence here is estimated at 1:6000 or 0.017%.
(Wikipedia)
I have also read that it is more prevalent in Scandinavian countries.