Year	Measure
1800	1198
1820	1198
1850	1522
1870	1642
1890	2123
1900	2439
1910	2808
1913	2956
1920	2727
1921	2941
1922	2829
1923	3034
1924	3319
1925	3676
1926	3633
1927	3881
1928	4199
1929	4291
1930	4127
1931	3962
1932	3780
1933	3599
1934	3446
1935	3399
1936	3666
1937	4065
1948	4356
1949	4598
1950	4938
1951	4970
1952	5075
1953	4999
1954	5151
1955	5532
1956	5797
1957	6093
1958	6503
1959	6742
1960	7206
1961	7424
1962	7481
1963	7292
1964	7578
1965	7804
1966	8097
1967	8413
1968	8777
1969	8963
1970	9121
1971	9392
1972	9674
1973	9932
1974	10220
1975	10440
1976	10520
1977	10920
1978	10980
1979	11010
1980	11260
1981	11160
1982	11350
1983	11490
1984	11740
1985	11800
1986	12000
1987	12040
1988	12280
1989	12370
1990	12010
1991	10220
1992	9498
1993	9637
1994	10200
1995	10760
1996	11480
1997	12130
1998	12560
1999	12600
2000	12690
2001	13100
2002	13640
2003	14210
2004	14980
2005	15880
2006	17180
2007	18970
2008	20040
2009	19010
2010	19790
2011	20380
2012	20780
2013	21050
2014	21600
2015	22280
2016	23040
2017	23830
2018	24650