Year	Number
1960	11212
1961	11381
1962	11544
1963	11719
1964	12028
1965	12444
1966	12842
1967	13242
1968	13635
1969	14007
1970	14114
1971	13932
1972	13672
1973	13356
1974	13004
1975	12631
1976	12270
1977	11951
1978	11652
1979	11385
1980	11127
1981	10840
1982	10553
1983	10291
1984	10012
1985	9769
1986	9615
1987	9497
1988	9422
1989	9393
1990	9405
1991	9414
1992	9453
1993	9562
1994	9701
1995	9865
1996	10058
1997	10235
1998	10364
1999	10449
2000	10529
2001	10579
2002	10552
2003	10495
2004	10427
2005	10327
2006	10236
2007	10184
2008	10157
2009	10144
2010	10070
2011	9942
2012	9800
2013	9657
2014	9529
2015	9381
2016	9212
2017	9067
2018	8928
2019	8800
2020	8711
2021	8644
2022	8568
2023	8448