Year	Measure
1800	570
1820	570
1950	2084
1951	2270
1952	2388
1953	2375
1954	2314
1955	2845
1956	3386
1957	3448
1958	3706
1959	3902
1960	4903
1961	5238
1962	6757
1963	8862
1964	12160
1965	15130
1966	17350
1967	18770
1968	24310
1969	26440
1970	26910
1971	24600
1972	21010
1973	20260
1974	16510
1975	17100
1976	20470
1977	21950
1978	22310
1979	24380
1980	23660
1981	18560
1982	17360
1983	16640
1984	14870
1985	13500
1986	12370
1987	11770
1988	11620
1989	11480
1990	11070
1991	10230
1992	9640
1993	9056
1994	8810
1995	8738
1996	9051
1997	9467
1998	8998
1999	8967
2000	9140
2001	9540
2002	9535
2003	9954
2004	10300
2005	10800
2006	11260
2007	11720
2008	11790
2009	11480
2010	11840
2011	4550
2012	9136
2013	10780
2014	11660
2015	12480
2016	13300
2017	13710
2018	14140