1910     0.000
1911    23.440
1912    32.100
1913    18.300
1914    19.340
1915    23.540
1916    24.620
1917    34.660
1918    19.040
1919    20.420
1920    26.420
1921    25.580
1922    16.480
1923    15.840
1924    19.080
1925    14.600
1926    20.880
1927    19.640
1928    14.140
1929    26.860
1930    12.200
1931    27.660
1932    16.000
1933    19.000
1934    43.620
1935    13.100
1936    19.640
1937    12.980
1938    17.680
1939    16.860
1940    27.160
1941    27.660
1942    13.700
1943    12.740
1944    12.180
1945    11.280
1946     8.540
1947     7.620
1948    12.780
1949    18.460
1950    20.580
1951    20.560
1952    12.900
1953    21.560
1954    27.940
1955    19.460
1956    23.120
1957    15.080
1958    16.800
1959    15.220
1960     8.560
1961    15.760
1962     7.060
1963    18.160
1964    20.600
1965    18.600
1966    15.000
1967    11.640
1968    12.460
1969    13.620
1970    10.520
1971    10.380
1972    10.480
1973    23.620
1974    10.540
1975    19.600
1976    17.700
1977    12.800
1978    21.400
1979    31.060
1980    10.940
1981    21.740
1982    20.300
1983    30.240
1984    25.160
1985    19.980
1986    15.640
1987    23.120
1988    18.320
1989    12.800
1990    17.300
1991    19.380
1992    23.840
1993    29.060
1994    14.400
1995    16.260
1996    30.500
1997    20.600
1998    39.240
1999    28.780
2000    25.960
2001    18.700
2002    23.600
2003    29.440
2004    18.620
2005    28.740
2006    30.700
2007    37.620
2008    19.360
2009    17.860
2010    23.060
2011    30.500
2012    46.280