1910    19.380
1911    29.740
1912    33.440
1913    21.200
1914    21.480
1915    23.120
1916    24.060
1917    33.880
1918    16.080
1919    14.800
1920    22.180
1921    26.620
1922    20.240
1923    13.040
1924    28.780
1925    21.960
1926    24.900
1927    18.560
1928    10.760
1929    26.940
1930    10.320
1931    27.000
1932    13.260
1933    19.460
1934    42.100
1935    13.300
1936    18.240
1937    21.900
1938    16.180
1939    10.500
1940    30.740
1941    23.020
1942    15.240
1943    13.140
1944    14.060
1945    11.180
1946    13.940
1947    14.300
1948    14.460
1949    24.320
1950    22.740
1951    17.040
1952    14.840
1953    18.180
1954    26.120
1955    22.160
1956    14.840
1957    15.720
1958    24.640
1959     9.040
1960    18.420
1961    16.060
1962     7.840
1963    12.640
1964    18.740
1965    14.000
1966    12.480
1967     9.220
1968    12.780
1969    11.380
1970    11.740
1971    13.960
1972    14.140
1973    24.020
1974    15.240
1975    20.120
1976    11.700
1977    13.600
1978    27.700
1979    33.600
1980    11.180
1981    19.880
1982    16.960
1983    26.740
1984    19.380
1985    14.220
1986    24.840
1987    23.220
1988    21.560
1989    14.580
1990    22.860
1991    23.580
1992    25.560
1993    25.680
1994    15.500
1995    15.820
1996    25.460
1997    18.760
1998    32.840
1999    21.520
2000    30.160
2001    12.800
2002    23.640
2003    24.820
2004    16.520
2005    18.900
2006    38.780
2007    27.820
2008    19.880
2009    17.960
2010    23.980
2011    35.240
2012    46.000