Year	Number
1960	13268
1961	13643
1962	13950
1963	14241
1964	14530
1965	14864
1966	15244
1967	15657
1968	16103
1969	16560
1970	16773
1971	16648
1972	16438
1973	16238
1974	16040
1975	15839
1976	15633
1977	15417
1978	15182
1979	14923
1980	14625
1981	14174
1982	13581
1983	13027
1984	12578
1985	12214
1986	11922
1987	11706
1988	11577
1989	11535
1990	11548
1991	11548
1992	11490
1993	11412
1994	11329
1995	11225
1996	11095
1997	10937
1998	10746
1999	10522
2000	10269
2001	10023
2002	9807
2003	9606
2004	9404
2005	9199
2006	8992
2007	8776
2008	8557
2009	8348
2010	8142
2011	7962
2012	7834
2013	7665
2014	7631
2015	7583
2016	7394
2017	7294
2018	7225
2019	7199
2020	7166
2021	7109
2022	7043
2023	6973