Year	Number
1960	11858
1961	12011
1962	12120
1963	12182
1964	12230
1965	12308
1966	12431
1967	12608
1968	12816
1969	13007
1970	13207
1971	13404
1972	13499
1973	13462
1974	13321
1975	13093
1976	12879
1977	12708
1978	12484
1979	12196
1980	11891
1981	11657
1982	11507
1983	11375
1984	11242
1985	11121
1986	11070
1987	11110
1988	11181
1989	11283
1990	11404
1991	11576
1992	11813
1993	12032
1994	12196
1995	12293
1996	12413
1997	12561
1998	12656
1999	12703
2000	12660
2001	12652
2002	12734
2003	12778
2004	12782
2005	12761
2006	12702
2007	12616
2008	12522
2009	12430
2010	12348
2011	12314
2012	12334
2013	12371
2014	12395
2015	12427
2016	12451
2017	12533
2018	12752
2019	13005
2020	13179
2021	13261
2022	13291
2023	13298