1913    254.40
  1914    254.40
  1915    252.60
  1916    252.60
  1917    252.60
  1918    252.60
  1919    252.60
  1920    252.60
  1921    253.80
  1922    257.00
  1923    250.40
  1924    257.80
  1925    255.20
  1926    251.90
  1927    256.80
  1928    251.00
  1929    250.40
  1930    250.40
  1931    249.20
  1932    249.20
  1933    247.60
  1934    246.80
  1935    246.80
  1936    246.80
  1937    246.40
  1938    247.20
  1939    247.40
  1940    248.30
  1941    248.60
  1942    244.60
  1943    242.60
  1944    241.60
  1945    241.40
  1946    246.60
  1947    247.00
  1948    248.80
  1949    245.40
  1950    246.20
  1951    241.40
  1952    242.10
  1953    242.00
  1954    237.90
  1955    239.00
  1956    238.60
  1957    237.20
  1958    234.50
  1959    236.50
  1960    237.00
  1961    237.60
  1962    234.40
  1963    234.90
  1964    234.10
  1965    233.60
  1966    231.30
  1967    231.10
  1968    233.80
  1969    235.90
  1970    236.30
  1971    234.40
  1972    232.80
  1973    232.00
  1974    233.20
  1975    229.40
  1976    233.10
  1977    232.00
  1978    232.50
  1979    228.95
  1980    228.80
  1981    227.33
  1982    227.69
  1983    229.21
  1984    229.54
  1985    226.32
  1986    228.31
  1987    226.76
  1988    228.85
  1989    229.90
  1990    229.31
  1991    229.12
  1992    228.80
  1993    224.39
  1994    228.67
  1995    225.19
  1996    228.15
  1997    224.90