Year	Number
1960	21797
1961	21907
1962	22106
1963	22442
1964	22766
1965	23022
1966	23198
1967	23281
1968	23481
1969	23875
1970	24270
1971	24610
1972	24889
1973	25102
1974	25262
1975	25524
1976	25898
1977	26242
1978	26553
1979	26834
1980	27076
1981	27284
1982	27573
1983	27985
1984	28407
1985	28807
1986	29171
1987	29500
1988	29802
1989	30078
1990	30329
1991	30564
1992	30794
1993	31024
1994	31253
1995	31482
1996	31719
1997	31968
1998	32209
1999	32394
2000	32465
2001	32444
2002	32386
2003	32316
2004	32236
2005	32141
2006	32011
2007	31823
2008	31862
2009	32401
2010	33178
2011	33945
2012	34700
2013	35425
2014	36110
2015	36760
2016	37071
2017	37044
2018	37029
2019	37034
2020	36922
2021	36686
2022	36469
2023	36297