# year    value 
 1901 10.74141 
 1902 10.04836 
 1903 10.21475 
 1904 9.959581 
 1905 9.670255 
 1906 10.23435 
 1907 9.819098 
 1908 9.837379 
 1909 9.970695 
 1910 10.54466 
 1911  10.0474 
 1912   10.453 
 1913 10.65209 
 1914 9.954961 
 1915 10.70169 
 1916 10.64991 
 1917 10.67652 
 1918 10.05411 
 1919 10.08612 
 1920  10.3126 
 1921  10.4297 
 1922 10.55317 
 1923 10.12522 
 1924  10.2956 
 1925 10.09228 
 1926 10.11979 
 1927 10.40222 
 1928  10.5829 
 1929 10.17749 
 1930 10.30789 
 1931 9.945816 
 1932  10.4913 
 1933 10.33151 
 1934 10.09305 
 1935  9.64086 
 1936 10.14417 
 1937 10.26109 
 1938 10.41782 
 1939 9.890066 
 1940 10.17426 
 1941 10.06261 
 1942 10.64012 
 1943 10.16714 
 1944 10.76108 
 1945 10.78799 
 1946 10.15814 
 1947 10.60853 
 1948 10.27416 
 1949 10.56644 
 1950  9.73256 
 1951 10.16005 
 1952 10.72811 
 1953 10.33453 
 1954 10.28766 
 1955  10.3889 
 1956 10.33908 
 1957 10.22565 
 1958 10.57608 
 1959 10.34628 
 1960 10.48055 
 1961 10.51767 
 1962 10.89863 
 1963 9.900681 
 1964 10.27187 
 1965 10.47784 
 1966 10.26204 
 1967 10.54315 
 1968 10.36861 
 1969 10.20421 
 1970  10.4728 
 1971 10.63682 
 1972 10.43056 
 1973 10.40397 
 1974 10.11368 
 1975 10.29942 
 1976 10.01563 
 1977 10.78747 
 1978 10.40764 
 1979  10.0543 
 1980 10.69797 
 1981 10.29169 
 1982 10.49095 
 1983  10.7293 
 1984  10.6103 
 1985 10.99005 
 1986 10.43984 
 1987 10.86729 
 1988 10.76293 
 1989 10.83296 
 1990 10.62748 
 1991 10.46306 
 1992   10.198 
 1993 10.60069 
 1994 10.55125 
 1995  10.6671 
 1996 10.76856 
 1997 10.60323 
 1998 10.81147 
 1999 11.17059 
 2000 10.13634 
 2001  10.6703 
 2002 10.60886 
 2003 10.82874 
 2004 10.90922 
 2005 10.84935 
 2006 11.00153 
 2007 10.79622 
 2008 11.10739 
 2009  10.3767 
 2010 10.83982 
 2011 11.02291 
 2012 11.05205 
 2013 10.87315 
 2014   11.233 
 2015  10.5706 
 2016 11.27232 
 2017 11.07051 
 2018 10.95103