Decided to google some,
In all of EU, 40% of people have a credit card. You're right that it varies greatly throughout the countries.
The highest credit card per capita rate is in Luxembourg, with around 3 per capita (for comparison's sake, in the US it's 3.5 per capita, in most EU countries at 1 per capita).
The highest ownership rate is in Luxembourg, with 87% of people having one. The lowest is in Hungary, with only 9% of the people having a credit card.
Some other countries: Denmark 71%, Bulgaria 12%, Lithuania 16%, Romania 17%. The rest of the EU countries can be seen here, on page 13
http://ec.europa.eu/public_opinion/archives/ebs/ebs_373_en.p...