thanks, I too have been googling since my post.  I'm finding the same thing you refer to--a number of links.  But also finding that some of the better stuff is available in books, rather than online.  So it could be a heavy slog, getting at this one, I'm afraid.  I did download the pdf associated with the reference you link to.  It seeems to have reviewed UK, US, Canada, and Northern Europe--I think it's the one (I've skimmed a few now) that included Germany, but felt its sample size was too small.  I'm noticing that as I skim, there seems to be data on the UK and Northern Europe, but not France, Italy, Spain (data lacking on Germany), etc.  I hope that there is more data on the rest of Europe, because I think it's going to be difficult use only the Scandanavian countries as a benchmark for continental Europe, as I think they are somewhat unique in terms of homogeneous population as compared to the other countries, and in some cases natural resources.

this is looking a lot bigger than I can take on right now, unfortunately.  It's very interesting, but would require significant study to get it right.