Year	Measure
1800	1309
1820	1336
1870	1481
1890	2085
1900	2230
1910	2613
1913	2614
1920	2550
1921	2575
1922	2613
1923	2710
1924	2864
1925	2962
1926	3124
1927	3030
1928	3250
1929	3373
1930	3260
1931	3118
1932	2789
1933	2836
1934	2901
1935	2818
1936	3141
1937	3149
1938	3354
1939	3491
1947	3253
1948	3829
1949	4150
1950	3835
1951	3934
1952	3581
1953	4062
1954	4233
1955	4444
1956	4307
1957	4981
1958	5143
1959	5721
1960	6026
1961	6235
1962	6290
1963	6877
1964	7466
1965	7593
1966	7925
1967	7992
1968	8092
1969	8926
1970	9284
1971	10260
1972	10520
1973	10780
1974	12070
1975	11960
1976	12210
1977	12980
1978	13580
1979	14390
1980	14990
1981	15170
1982	15180
1983	15230
1984	15530
1985	15570
1986	16130
1987	15870
1988	15580
1989	15310
1990	14140
1991	12990
1992	9325
1993	6479
1994	6639
1995	7012
1996	7344
1997	7914
1998	8133
1999	6302
2000	6607
2001	6940
2002	7236
2003	7436
2004	8082
2005	8609
2006	8954
2007	9476
2008	9878
2009	9571
2010	9438
2011	9503
2012	9336
2013	9523
2014	9713
2015	9927
2016	10180
2017	10450
2018	10770