Spending a week in a hotel in Croatia doesn't seem quite so cheap if your salary is paid in Croatia, which is why although the press release doesn't qualify "holiday" it does provide a country by country breakdown indicating that most Romanians and Croatians and very few Swedes feel priced out of an annual holiday. Agreed that your own index sounds like it would be useful data for other reasons.
The more notable thing is just how sharp the downward trend in the number of people saying they were unable to afford a holiday has been. http://appsso.eurostat.ec.europa.eu/nui/show.do?query=BOOKMA...