Year	Number
1960	20324
1961	21006
1962	21684
1963	22322
1964	22913
1965	23495
1966	24012
1967	24450
1968	24875
1969	25297
1970	25729
1971	26162
1972	26567
1973	26868
1974	26768
1975	26315
1976	25835
1977	25374
1978	24918
1979	24706
1980	24752
1981	24831
1982	24973
1983	25208
1984	25572
1985	26108
1986	26829
1987	27681
1988	28592
1989	29528
1990	30436
1991	31285
1992	32065
1993	32767
1994	33362
1995	33892
1996	34417
1997	34906
1998	35338
1999	35698
2000	36000
2001	36389
2002	36809
2003	37128
2004	37458
2005	37872
2006	38192
2007	38401
2008	38687
2009	39019
2010	39321
2011	39676
2012	40113
2013	40553
2014	41033
2015	41599
2016	42280
2017	43070
2018	43958
2019	44871
2020	45769
2021	46615
2022	47346
2023	47941