Year	Measure
1800	1227
1820	1253
1870	1290
1890	1816
1900	1943
1910	2276
1913	2276
1920	2221
1921	2243
1922	2276
1923	2360
1924	2494
1925	2580
1926	2721
1927	2639
1928	2830
1929	2938
1930	2839
1931	2715
1932	2429
1933	2470
1934	2527
1935	2454
1936	2735
1937	2743
1938	2921
1939	3040
1947	2833
1948	3335
1949	3615
1950	3340
1951	3427
1952	3119
1953	3538
1954	3687
1955	3871
1956	3751
1957	4338
1958	4479
1959	4983
1960	5248
1961	5430
1962	5478
1963	5990
1964	6502
1965	6613
1966	6902
1967	6960
1968	7048
1969	7774
1970	8086
1971	8939
1972	9164
1973	9391
1974	10510
1975	10420
1976	10640
1977	11310
1978	11830
1979	12530
1980	13060
1981	13210
1982	13220
1983	13260
1984	13520
1985	13560
1986	14050
1987	13820
1988	13570
1989	13340
1990	12320
1991	9654
1992	8448
1993	7700
1994	8100
1995	8637
1996	9177
1997	9876
1998	10230
1999	10230
2000	10580
2001	11070
2002	11630
2003	12080
2004	12490
2005	13230
2006	13890
2007	14610
2008	14920
2009	13900
2010	13620
2011	13660
2012	13390
2013	13360
2014	13560
2015	13830
2016	14110
2017	14460
2018	14820