# year    value 
 1900 15.95693 
 1901 15.79781 
 1902 15.85693 
 1903 15.44365 
 1904  15.6392 
 1905 15.70897 
 1906 15.79544 
 1907 15.62683 
 1908 15.69083 
 1909 15.83335 
 1910 15.86585 
 1911 15.82056 
 1912 15.62698 
 1913 15.52937 
 1914 15.75225 
 1915 15.84131 
 1916 15.81926 
 1917 15.94172 
 1918 16.05741 
 1919 15.90092 
 1920 16.00218 
 1921 15.94322 
 1922 15.90446 
 1923 15.96937 
 1924 16.02186 
 1925 15.99384 
 1926 15.99437 
 1927 16.01682 
 1928  16.0815 
 1929 16.03954 
 1930 15.96699 
 1931 15.97495 
 1932 16.01287 
 1933 16.00155 
 1934 15.91821 
 1935 15.98623 
 1936  16.1078 
 1937 16.08739 
 1938 16.15638 
 1939 16.00818 
 1940  16.1674 
 1941 16.07686 
 1942 16.09382 
 1943 16.20191 
 1944 16.15799 
 1945 16.18411 
 1946 16.00567 
 1947  16.1534 
 1948 16.15332 
 1949 16.14166 
 1950 16.13938 
 1951 16.08189 
 1952 16.02729 
 1953 15.91583 
 1954 16.07072 
 1955 16.04259 
 1956 16.10573 
 1957 16.06063 
 1958 16.07395 
 1959 15.98804 
 1960 16.07652 
 1961  16.0577 
 1962 16.05385 
 1963 16.03933 
 1964 15.88063 
 1965 15.92467 
 1966 15.93854 
 1967 16.03489 
 1968 15.98528 
 1969 15.94843 
 1970 16.09246 
 1971 16.13999 
 1972 16.12112 
 1973 16.12246 
 1974 16.07733 
 1975 16.19271 
 1976 16.17606 
 1977 16.12253 
 1978 16.23814 
 1979 16.30173 
 1980 16.42892 
 1981 16.34761 
 1982 16.25659 
 1983 15.90877 
 1984 16.15681 
 1985 16.33017 
 1986 16.25021 
 1987 16.38041 
 1988 16.39489 
 1989  16.5019 
 1990 16.54343 
 1991 16.52903 
 1992 16.10607 
 1993 16.32473 
 1994 16.42839 
 1995 16.44888 
 1996  16.6237 
 1997 16.72146 
 1998  16.7075 
 1999 16.78523 
 2000 16.87884 
 2001 16.97766 
 2002 16.86044 
 2003 16.88202 
 2004 16.90436 
 2005 17.05399