Year	Number
1960	2539
1961	2797
1962	3074
1963	3362
1964	3654
1965	3936
1966	4272
1967	4717
1968	5189
1969	5615
1970	5995
1971	6349
1972	6678
1973	6983
1974	7272
1975	7543
1976	7803
1977	8048
1978	8259
1979	8410
1980	8451
1981	8378
1982	8497
1983	8799
1984	8977
1985	9000
1986	9084
1987	9282
1988	9418
1989	9501
1990	9529
1991	9557
1992	9622
1993	9707
1994	9813
1995	9939
1996	10006
1997	10024
1998	10056
1999	10086
2000	10098
2001	10339
2002	10815
2003	11270
2004	11676
2005	11978
2006	12108
2007	12086
2008	12007
2009	11884
2010	11671
2011	11598
2012	11655
2013	11598
2014	11416
2015	11123
2016	11006
2017	10851
2018	10573
2019	10437
2020	10361
2021	10333
2022	10213
2023	9947