1910    17.633
1911    18.900
1912    23.167
1913    18.783
1914    17.450
1915    37.517
1916    28.967
1917    19.117
1918    19.150
1919    19.667
1920    14.633
1921    18.700
1922    10.783
1923    14.133
1924    19.033
1925    15.433
1926    17.283
1927    22.033
1928    22.150
1929    14.267
1930    15.983
1931    21.717
1932    16.683
1933    23.317
1934    32.183
1935     8.600
1936    37.550
1937    14.717
1938    10.650
1939    12.550
1940    19.517
1941    17.850
1942    16.967
1943    20.133
1944    17.650
1945    19.567
1946    12.050
1947    13.900
1948    10.150
1949    18.817
1950    23.117
1951    19.300
1952    17.767
1953    21.267
1954    27.900
1955    19.767
1956    14.400
1957    17.100
1958    16.000
1959    13.817
1960    12.600
1961    21.317
1962     7.867
1963    12.533
1964    16.233
1965    16.433
1966    13.233
1967    20.783
1968    12.117
1969    15.533
1970    16.250
1971     7.350
1972    15.733
1973    13.583
1974    13.450
1975    12.550
1976    23.283
1977    10.367
1978    11.567
1979    15.467
1980    25.267
1981    15.083
1982    11.467
1983    26.700
1984    14.217
1985    17.500
1986    13.433
1987    10.950
1988    24.983
1989    18.117
1990     9.833
1991    20.600
1992    41.700
1993    31.833
1994    17.983
1995    23.767
1996    18.283
1997    16.583
1998    23.117
1999    17.383
2000    16.383
2001    16.383
2002    24.067
2003    26.183
2004    33.733
2005    34.683
2006    25.450
2007    29.933
2008    23.000
2009    20.450
2010    25.317
2011    38.183
2012    29.667