Year	Number
1960	4091
1961	4154
1962	4235
1963	4340
1964	4505
1965	4715
1966	4942
1967	5202
1968	5492
1969	5803
1970	6084
1971	6329
1972	6596
1973	6892
1974	7211
1975	7551
1976	7917
1977	8308
1978	8695
1979	9064
1980	9431
1981	9823
1982	10236
1983	10657
1984	11072
1985	11441
1986	11748
1987	11996
1988	12170
1989	12303
1990	12512
1991	12773
1992	13007
1993	13273
1994	13644
1995	14056
1996	14405
1997	14774
1998	15194
1999	15685
2000	16306
2001	16941
2002	17520
2003	18111
2004	18772
2005	19491
2006	20222
2007	20984
2008	21736
2009	22439
2010	23116
2011	23851
2012	24715
2013	25631
2014	26583
2015	27604
2016	28627
2017	29655
2018	30846
2019	32234
2020	33651
2021	34949
2022	36452
2023	38308