Year	Number
1960	11878
1961	12118
1962	12315
1963	12459
1964	12536
1965	12544
1966	12495
1967	12343
1968	12110
1969	11867
1970	11602
1971	11305
1972	11030
1973	10792
1974	10547
1975	10303
1976	10009
1977	9694
1978	9451
1979	9273
1980	9156
1981	9127
1982	9124
1983	9108
1984	9089
1985	9015
1986	8872
1987	8687
1988	8528
1989	8539
1990	8867
1991	9537
1992	9998
1993	10083
1994	10144
1995	10127
1996	10089
1997	10116
1998	10207
1999	10349
2000	10461
2001	10476
2002	10429
2003	10350
2004	10240
2005	10210
2006	10304
2007	10425
2008	10540
2009	10635
2010	10602
2011	10437
2012	10280
2013	10164
2014	10079
2015	10012
2016	9947
2017	9869
2018	9772
2019	9651
2020	9438
2021	9133
2022	8820
2023	8520