The report breaks down the countries into three groups -- those in which trafficking is organised, transit countries, and destination countries for people being trafficked.
Croatia is in the medium intensity group in all three categories.
Countries with a very high degree of organised criminal trafficking in humans are Albania, Belarus, Bulgaria, Lithuania, Moldova, Romania, Russia, and Ukraine.
A high degree was recorded in Armenia, the Czech Republic, Estonia, Georgia, Hungary, Latvia, Poland, and Slovakia.
Countries of very high transit are Albania, Bulgaria, Hungary, Italy and Poland. Those of high transit are Belgium, Bosnia and Herzegovina, the Czech Republic, France, Germany, Greece, Kosovo, Romania, Serbia, Montenegro, Slovakia, Macedonia, Turkey, and Ukraine.
The destination countries for human slaves in Europe are Belgium, Germany, Greece, Italy, the Netherlands, and Turkey.
UNODC Executive Director Antonio Maria Costa said the victims of trafficking were mainly women and children, and that trafficking in humans was mainly characterised by sexual exploitation and slave labour.