Take it with a grain of salt because this is from a pharmaceutical group, but this page claims the average body temperature of the Japanese was 36.89°C 50 years ago and that it was 36.20°C as of 2009. http://www.sawai.co.jp/kenko-suishinka/illness/200909-02.htm...

Edit: although, that might as well be due to the aging population. That said, I have been told that my average (by France standards) temperature was "a little high".