Year	Number of
1952	14100
1953	13950
1954	14040
1955	14320
1956	14780
1957	15330
1958	15810
1959	16120
1960	16110
1961	15640
1962	14970
1963	14170
1964	13430
1965	12940
1966	12680
1967	12670
1968	12660
1969	12640
1970	12430
1971	12030
1972	11430
1973	10760
1974	10190
1975	9758
1976	9511
1977	9300
1978	9146
1979	8863
1980	8390
1981	7901
1982	7409
1983	7065
1984	6851
1985	6548
1986	6223
1987	5821
1988	5375
1989	4990
1990	4814
1991	4801
1992	4815
1993	4818
1994	4723
1995	4534
1996	4323
1997	4032
1998	3768
1999	3534
2000	3387
2001	3326
2002	3337
2003	3365
2004	3458
2005	3248
2006	3079
2007	2885
2008	2672
2009	2485
2010	2292
2011	2129
2012	1997
2013	1867
2014	1782
2015	1683