Year	Number
1960	21822
1961	21907
1962	22249
1963	22796
1964	23347
1965	23910
1966	24477
1967	25047
1968	25610
1969	26162
1970	26685
1971	27069
1972	27323
1973	27558
1974	27779
1975	27973
1976	28162
1977	28337
1978	28485
1979	28618
1980	28734
1981	28819
1982	28863
1983	28855
1984	28788
1985	28674
1986	28506
1987	28272
1988	28000
1989	27688
1990	27317
1991	26988
1992	26945
1993	27118
1994	27282
1995	27412
1996	27491
1997	27564
1998	27636
1999	27695
2000	27741
2001	27721
2002	27892
2003	28301
2004	28716
2005	29155
2006	29587
2007	29996
2008	30398
2009	30819
2010	31262
2011	31701
2012	32160
2013	32411
2014	32452
2015	32520
2016	32565
2017	32602
2018	32648
2019	32685
2020	32709
2021	32669
2022	32649
2023	32688