Year	Number
1960	7607
1961	7948
1962	8300
1963	8657
1964	9023
1965	9397
1966	9760
1967	10132
1968	10547
1969	10809
1970	10865
1971	11343
1972	12019
1973	12745
1974	13473
1975	14156
1976	14831
1977	15487
1978	16138
1979	16759
1980	17340
1981	17895
1982	18399
1983	18851
1984	19245
1985	19637
1986	20015
1987	20283
1988	20378
1989	20614
1990	20911
1991	21207
1992	21522
1993	21966
1994	22391
1995	22812
1996	23229
1997	23656
1998	24119
1999	24586
2000	25063
2001	25627
2002	26270
2003	26878
2004	27393
2005	27871
2006	28382
2007	28856
2008	29246
2009	29664
2010	30261
2011	31183
2012	31863
2013	32077
2014	32240
2015	32475
2016	32789
2017	33059
2018	33209
2019	33278
2020	33156
2021	32942
2022	32897
2023	32914