Year	Number
1960	51632
1961	52310
1962	53116
1963	53945
1964	54701
1965	55392
1966	55782
1967	56151
1968	56740
1969	57275
1970	57613
1971	57962
1972	57109
1973	55537
1974	54659
1975	53472
1976	52095
1977	50678
1978	48935
1979	47501
1980	46400
1981	45541
1982	45054
1983	44555
1984	44133
1985	43884
1986	43568
1987	43030
1988	42276
1989	41559
1990	41101
1991	40797
1992	40603
1993	40555
1994	40380
1995	40186
1996	40097
1997	39785
1998	38566
1999	36642
2000	34589
2001	32781
2002	32259
2003	32326
2004	32253
2005	32428
2006	32702
2007	32943
2008	33014
2009	32882
2010	32933
2011	32997
2012	32849
2013	32823
2014	32862
2015	32832
2016	32575
2017	31885
2018	29663
2019	28044
2020	27446
2021	26516
2022	25728
2023	25057