1897,53.30
1898,53.20
1899,53.20
1900,53.50
1901,54.30
1902,54.50
1903,53.40
1904,53.20
1905,53.90
1906,53.20
1907,53.50
1908,53.70
1909,53.40
1910,53.90
1911,54.40
1912,52.60
1913,50.70
1914,52.00
1915,52.30
1916,52.60
1917,52.60
1918,52.50
1919,52.20
1920,51.60
1921,52.70
1922,53.40
1923,53.30
1924,52.50
1925,52.90
1926,52.80
1927,53.00
1928,53.60
1929,52.50
1930,52.00
1931,52.20
1932,52.30
1933,52.10
1934,53.80
1935,54.70
1936,53.60
1937,53.00
1938,53.10
1939,53.40
1940,53.30
1941,53.00
1942,52.60
1943,53.90
1944,53.60
1945,52.60
1946,53.50
1947,53.70
1948,53.30
1949,52.80
1950,53.20
1951,54.40
1952,54.30
1953,53.70
1954,54.20
1955,53.80
1956,53.70
1957,54.00
1958,53.40
1959,53.40
1960,53.30
1961,52.80
1962,52.70
1963,53.40
1964,53.20
1965,52.40
1966,53.00
1967,53.60
1968,53.10
1969,52.90
1970,53.10
1971,52.70
1972,53.10
1973,52.30
1974,52.40
1975,52.60
1976,52.30
1977,52.80
1978,53.30
1979,53.20
1980,53.00
1981,54.10
1982,54.20
1983,53.30
1984,52.80
1985,53.00
1986,53.80
1987,53.40
1988,52.40
1989,53.60
1990,54.10
1991,53.20
1992,52.90
1993,53.20
1994,53.70
1995,54.10
1996,54.70
1997,54.60
1998,53.70
1999,54.00
2000,55.40
2001,55.00
2002,54.50
2003,55.00
2004,54.60
2005,54.30
2006,54.60
2007,54.30
2008,53.70
2009,54.30
2010,54.20
2011,54.60
2012,55.40