Again a bit a strange mixture.
Basically its early porn talent pool traditions (Romania, Baltics) vs. fairly oppressive religious places with marginal talent pools (Poland, Croatia, Slovakia).
Ukraine is an own talent pool, post Soviet like Russia, but tapped quite late after Hungarian police shut down Nicoletta's import biz in mid2000. Its growing due to EU visa liberations.
Hungary sticks out in terms of Europorn history, though talent pool there is currently dried up even more than in Czech it seems.