I thought the same, though the difference is large enough to warrant scrutiny. Ideally Eurostat would have collected data for a few non-EU countries to compare

I thought the same, though the difference is large enough to warrant scrutiny. Ideally Eurostat would have collected data for a few non-EU countries to compare against, but this doesn't fit within their scope as a Directorate-General of the European Commission. It's definitely in their interest to show that Europeans are happy.