X1 x2 1895 49.4 1896 49.04 1897 49.8 1898 49.49 1899 49.02 1900 50.44 1901 49.44 1902 49.13 1903 49.96 1904 51.31 1905 51 1906 52.04 1907 50.68 1908 49.94 1909 48.96 1910 50.6 1911 49.77 1912 50.7 1913 49.68 1914 51.27 1915 51.39 1916 47.92 1917 50.4 1918 51.09 1919 49.04 1920 49.33 1921 50.47 1922 48.72 1923 50.79 1924 50.15 1925 51.78 1926 52.52 1927 50.24 1928 50.84 1929 49.97 1930 50.35 1931 52.11 1932 51.43 1933 50.75 1934 54.22 1935 50.8 1936 51.29 1937 50.77 1938 51.95 1939 52.44 1940 53.3 1941 53.17 1942 51.41 1943 50.85 1944 51.32 1945 51.26 1946 51.05 1947 52.19 1948 49.7 1949 50.45 1950 50.08 1951 51.26 1952 51.01 1953 51.96 1954 49.83 1955 48.52 1956 50.16 1957 50.72 1958 53.87 1959 50.72 1960 50.19 1961 51.88 1962 50.79 1963 50.76 1964 48.84 1965 51.77 1966 51.2 1967 52.05 1968 50.98 1969 50.64 1970 50.62 1971 50.01 1972 50.15 1973 50.32 1974 50.17 1975 49.14 1976 49.05 1977 49.75 1978 49.86 1979 50.12 1980 50.04 1981 51.17 1982 49.93 1983 50.82 1984 50.1 1985 48.34 1986 51.96 1987 52.1 1988 51.4 1989 51.08 1990 51.7 1991 51.4 1992 53.68 1993 50.92 1994 52.26