1900  246.0
1920  241.9
1936  227.8
1948  229.8
1960  218.4
1968  214.9
1972  216.3
1976  219.2
1980  218.4
1984  212.5
1988  216.0
1992  220.1
1996  215.8
2000  212.1
2004  214.2
2008  212.9