Results of Institute of Tourism' surveys are usually presented in the following order:
first come data about the World (all tourists), then the neighbouring countries from the west side (Germany) and from the east (Russia, Ukraine, Belarus - altogether). Neighbours generate a huge portion of inbound traffic to Poland.
And then follows: tourists from EU-15 (exl. Germany, presented separately) and new EU members. The last group – "overseas" comprises USA, Canada, Japan, Australia and Korea Rep.

See [ a set of detailed tables 2001-2006 ],  

[ Some graphs from 2005 survey,  2006 survey and 2007 survey ]

or [ graphs on trends in inbound tourism 2000-2005 ]