Year	Number
1960	8318
1961	8692
1962	9059
1963	9429
1964	9805
1965	10192
1966	10580
1967	10956
1968	11315
1969	11650
1970	11948
1971	12152
1972	12338
1973	12384
1974	12453
1975	12572
1976	12627
1977	12660
1978	12525
1979	12446
1980	12388
1981	12380
1982	12263
1983	12055
1984	11971
1985	11933
1986	11877
1987	12252
1988	12120
1989	11973
1990	11783
1991	11730
1992	11625
1993	11667
1994	11793
1995	11785
1996	11734
1997	11793
1998	11957
1999	11969
2000	11854
2001	11655
2002	11809
2003	11479
2004	11218
2005	11076
2006	11116
2007	10996
2008	11093
2009	10959
2010	11065
2011	10582
2012	10573
2013	10725
2014	10851
2015	11065
2016	11216
2017	11374
2018	11484
2019	11567
2020	11625
2021	11677
2022	14070
2023	13986