Year	Number
1960	4041
1961	4228
1962	4405
1963	4576
1964	4743
1965	4915
1966	5096
1967	5278
1968	5460
1969	5683
1970	6001
1971	6287
1972	6482
1973	6666
1974	6826
1975	6938
1976	6978
1977	7028
1978	7152
1979	7316
1980	7512
1981	7740
1982	7993
1983	8270
1984	8563
1985	8871
1986	9150
1987	9380
1988	9626
1989	9914
1990	10216
1991	10534
1992	10875
1993	11234
1994	11612
1995	12012
1996	12428
1997	12856
1998	13305
1999	13806
2000	14275
2001	14679
2002	15091
2003	15508
2004	15924
2005	16334
2006	16745
2007	17171
2008	17617
2009	18076
2010	18552
2011	19035
2012	19526
2013	20040
2014	20577
2015	21118
2016	21663
2017	22228
2018	22802
2019	23385
2020	23935
2021	24473
2022	25107
2023	25885