Year	Number
1960	7786
1961	8058
1962	8300
1963	8572
1964	8878
1965	9216
1966	9578
1967	9954
1968	10327
1969	10682
1970	11010
1971	11272
1972	11475
1973	11675
1974	11889
1975	12128
1976	12396
1977	12674
1978	12937
1979	13158
1980	13315
1981	13416
1982	13475
1983	13514
1984	13553
1985	13605
1986	13667
1987	13725
1988	13760
1989	13744
1990	13663
1991	13595
1992	13552
1993	13486
1994	13433
1995	13361
1996	13264
1997	13162
1998	13087
1999	13059
2000	13070
2001	13119
2002	13198
2003	13367
2004	13615
2005	13854
2006	14092
2007	14346
2008	14621
2009	14927
2010	15287
2011	15720
2012	16237
2013	16753
2014	17252
2015	17783
2016	18323
2017	18873
2018	19792
2019	20564
2020	21026
2021	21503
2022	21882
2023	22621