Year Measure
1800 801.9
1820 828.9
1870 1416
1871 1441
1872 1436
1873 1501
1874 1547
1875 1540
1876 1515
1877 1547
1878 1605
1879 1698
1880 1799
1881 1803
1882 1609
1883 1547
1884 1566
1885 1599
1886 1605
1887 1577
1888 1632
1889 1702
1890 1774
1891 1816
1892 1932
1893 2058
1894 2080
1895 2035
1896 2076
1897 2062
1898 2000
1899 1998
1900 2074
1901 2164
1902 2223
1903 2223
1904 2226
1905 2378
1906 2431
1907 2525
1908 2505
1909 2476
1910 2652
1911 2764
1912 2783
1913 2909
1914 2844
1915 2790
1916 2460
1917 2406
1918 2265
1919 2622
1920 2210
1921 2429
1922 2725
1923 2577
1924 2745
1925 2739
1926 2948
1927 3237
1928 3360
1929 3552
1930 3926
1931 3864
1932 3688
1933 4067
1934 4095
1935 3944
1936 3935
1937 4083
1938 4083
1939 4538
1940 4774
1941 5411
1942 6238
1943 6575
1944 7112
1945 7563
1946 7759
1947 8432
1948 8439
1949 8116
1950 7750
1951 7469
1952 7268
1953 8211
1954 8801
1955 9459
1956 9489
1957 9244
1958 9790
1959 9769
1960 9890
1961 9724
1962 10350
1963 11220
1964 12130
1965 12790
1966 13700
1967 13320
1968 12440
1969 12660
1970 13530
1971 15130
1972 15800
1973 16670
1974 17380
1975 17300
1976 18180
1977 19650
1978 20650
1979 21450
1980 22430
1981 23120
1982 23270
1983 22500
1984 23220
1985 23820
1986 25110
1987 26920
1988 26440
1989 26320
1990 26370
1991 26330
1992 25140
1993 25030
1994 25940
1995 25840
1996 27030
1997 28060
1998 29260
1999 30040
2000 31090
2001 31830
2002 31160
2003 31940
2004 34280
2005 35630
2006 36360
2007 37840
2008 37920
2009 35090
2010 33320
2011 33930
2012 34370
2013 34830
2014 35380
2015 35930
2016 36340
2017 36850
2018 37520