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.
So is it fair to say "the percentage of Europeans who can't afford a 1 week annual holiday is steadily dropping and most recently sits at a low of 28%?"
The starting point for this series is the global financial crisis and the drop seems to be driven mostly by Eastern European countries whose economies have been rapidly growing over that time period.
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...