Year Measure
1800 541.6
1820 541.6
1830 541.6
1840 541.6
1850 1550
1860 2995
1870 4197
1871 4272
1872 4770
1873 5187
1874 5204
1875 4994
1876 4906
1877 5392
1878 5783
1879 4833
1880 5073
1881 5097
1882 4936
1883 4732
1884 5013
1885 4857
1886 4877
1887 4880
1888 4812
1889 5012
1890 5085
1891 5052
1892 5146
1893 5130
1894 4846
1895 4931
1896 5400
1897 5348
1898 5396
1899 5472
1900 5820
1901 5719
1902 6010
1903 6401
1904 6189
1905 6567
1906 6984
1907 7230
1908 6547
1909 6459
1910 7199
1911 7439
1912 7054
1913 6977
1914 7026
1915 7006
1916 6933
1917 6781
1918 6650
1919 7153
1920 7639
1921 6944
1922 6555
1923 6966
1924 6964
1925 7165
1926 6641
1927 6341
1928 6961
1929 7125
1930 6716
1931 6060
1932 5859
1933 6196
1934 6456
1935 6715
1936 7907
1937 8262
1938 8750
1939 8747
1940 8531
1941 8299
1942 9155
1943 9381
1944 9300
1945 9381
1946 9697
1947 10620
1948 9382
1949 10180
1950 11450
1951 10360
1952 10560
1953 10640
1954 11840
1955 11810
1956 12190
1957 12250
1958 12440
1959 13040
1960 12820
1961 13200
1962 13180
1963 13720
1964 14110
1965 14730
1966 15380
1967 14460
1968 14280
1969 15590
1970 15150
1971 15670
1972 16050
1973 16820
1974 17440
1975 16910
1976 17130
1977 16230
1978 16290
1979 16630
1980 16720
1981 17450
1982 17630
1983 17920
1984 18610
1985 18650
1986 18980
1987 19010
1988 18870
1989 18980
1990 18830
1991 18380
1992 18360
1993 19340
1994 20120
1995 20660
1996 21060
1997 21050
1998 20880
1999 21690
2000 21900
2001 22430
2002 23190
2003 23730
2004 24340
2005 24550
2006 25000
2007 25610
2008 25160
2009 24470
2010 24610
2011 24760
2012 25220
2013 25710
2014 26160
2015 26570
2016 27030
2017 27480
2018 27940