1896,54.2
1900,49.4
1904,49.2
1908,50
1912,48.2
1920,49.6
1924,47.6
1928,47.8
1932,46.2
1936,46.5
1948,46.2
1952,45.9
1956,46.7
1960,44.9
1964,45.1
1968,43.8
1972,44.66
1976,44.26
1980,44.6
1984,44.27
1988,43.87
1992,43.5
1996,43.49