Year	Number
1960	10347
1961	10716
1962	11079
1963	11419
1964	11727
1965	12026
1966	12290
1967	12522
1968	12760
1969	12985
1970	13204
1971	13426
1972	13636
1973	13796
1974	13749
1975	13518
1976	13278
1977	13051
1978	12823
1979	12701
1980	12700
1981	12722
1982	12776
1983	12880
1984	13056
1985	13329
1986	13699
1987	14135
1988	14599
1989	15072
1990	15520
1991	15950
1992	16366
1993	16743
1994	17069
1995	17361
1996	17640
1997	17895
1998	18124
1999	18317
2000	18478
2001	18658
2002	18842
2003	18988
2004	19136
2005	19312
2006	19452
2007	19564
2008	19717
2009	19896
2010	20064
2011	20247
2012	20458
2013	20669
2014	20898
2015	21173
2016	21512
2017	21907
2018	22359
2019	22836
2020	23319
2021	23789
2022	24207
2023	24558