Mercer Human Resource’s annual and oft-debated “Quality of Living” survey is out for 2010, ranking the quality of life in cities around the world. It’s good news for Canada, with four cities in the top 25 — while the U.S., we notice, has none.

Vancouverites will be glad to see that their city is number four, where it’s been holding steady since 2008. Ottawa comes in at #14, a big jump from #19 in 2008 and #16 in ’09.

Toronto drops one spot to #16, a still-strong showing, Montreal comes in at #21, a slight gain from last year’s #22, and Calgary is the big loser here, dropping all the way to #28, continuing the slow slide the nation’s oil capital has been on since 2008.  For what it’s worth, Calgary is still ranked higher than London, Tokyo and New York.

It’s important to note that the ranking isn’t a general “best cities” list — for that you can check out MoneySense’s Best Places to Live 2010 list. Rather, Mercer’s is a guide to help companies and governments place international employees. (Maybe that explains why Bern, Switzerland ranks higher than New York City.)