Year	Number
1960	15226
1961	15503
1962	15618
1963	15628
1964	15627
1965	15711
1966	15932
1967	16274
1968	16686
1969	17087
1970	17539
1971	18035
1972	18433
1973	18676
1974	18780
1975	18792
1976	18787
1977	18809
1978	18831
1979	18872
1980	19166
1981	19693
1982	20147
1983	20429
1984	20492
1985	20387
1986	20291
1987	20295
1988	20384
1989	20443
1990	20689
1991	21216
1992	21737
1993	22202
1994	22622
1995	23009
1996	23364
1997	23677
1998	23956
1999	24230
2000	24538
2001	24827
2002	25001
2003	25043
2004	24927
2005	24665
2006	24307
2007	23871
2008	23389
2009	22889
2010	22699
2011	22777
2012	22876
2013	22967
2014	23006
2015	23068
2016	23145
2017	23208
2018	23199
2019	23141
2020	23102
2021	23094
2022	23075
2023	23038