1850,10.9
1851,10.6
1852,10.6
1853,11.5
1854,13.3
1855,13.7
1856,13.7
1857,13.0
1858,11.9
1859,11.6
1860,12.1
1861,12.4
1862,12.1
1863,11.6
1864,11.5
1865,11.6
1866,12.4
1867,13.2
1868,13.0
1869,12.3
1870,12.3
1871,12.3
1872,13.1
1873,13.3
1874,12.7
1875,12.3
1876,12.0
1877,12.3
1878,12.0
1879,11.2
1880,11.6
1881,11.4
1882,11.5
1883,11.1
1884,10.9
1885,10.4
1886,10.0
1887,9.7
1888,9.7
1889,9.9
1890,9.9
1891,10.0
1892,10.0
1893,9.7
1894,9.5
1895,9.1
1896,9.0
1897,9.4
1898,9.5
1899,9.4
1900,9.7
1901,9.8
1902,9.9
1903,10.0
1904,10.1
1905,10.0
1906,10.0
1907,10.3
1908,10.6
1909,10.6
1910,10.7
1911,10.8
1912,11.2
1913,11.2
1914,11.1
1915,13.7
1916,16.2
1917,19.6
1918,22.6
1919,23.9
1920,27.7
1921,25.1
1922,20.4
1923,19.4
1924,19.5
1925,19.6
1926,19.1
1927,18.7
1928,18.5
1929,18.2
1930,17.6
1931,16.4
1932,16.0
1933,15.6
1934,15.7
1935,15.9
1936,16.4
1937,17.2
1938,17.4
1939,18.9
1940,21.8
1941,23.9
1942,24.0
1943,23.9
1944,24.1
1945,25.4
1946,29.0
1947,31.0
1948,33.3
1949,34.4
1950,35.1
1951,38.7
1952,40.5
1953,41.5
1954,42.3
1955,43.7
1956,45.8
1957,47.3
1958,48.7
1959,49.2
1960,49.8
1961,51.2
1962,53.0
1963,54.0
1964,55.8
1965,58.4
1966,60.7
1967,62.3
1968,65.2
1969,68.7
1970,73.1
1971,80.0
1972,85.7
1973,93.5
1974,108.5
1975,134.8
1976,157.1
1977,182.0
1978,197.1
1979,223.5
1980,263.7
1981,295.0
1982,320.4
1983,335.1
1984,351.8
1985,373.2
1986,385.9
1987,401.9
1988,421.6
1989,454.5
1990,497.6
1991,526.7
1992,546.4
1993,555.1
1994,568.5
1995,588.2
1996,602.4
1997,621.3
1998,642.6
1999,652.5
2000,671.8
2001,683.7
2002,695.1