Year	Number of
1969	10290
1970	10580
1971	10620
1972	10430
1973	10220
1974	10050
1975	9950
1976	9921
1977	9750
1978	9565
1979	9438
1980	9442
1981	9612
1982	9716
1983	9692
1984	9468
1985	9080
1986	8524
1987	7832
1988	7101
1989	6400
1990	5811
1991	5474
1992	5375
1993	5438
1994	5404
1995	4947
1996	4276
1997	3525
1998	2855
1999	2353
2000	2060
2001	1845
2002	1753
2003	1703
2004	1681
2005	1676
2006	1688
2007	1710
2008	1722
2009	1699
2010	1632
2011	1516
2012	1411
2013	1290
2014	1215
2015	1122