Year	Number
1960	9315
1961	9720
1962	10144
1963	10568
1964	10990
1965	11384
1966	11752
1967	12131
1968	12523
1969	12931
1970	13357
1971	13792
1972	14223
1973	14650
1974	15074
1975	15428
1976	15720
1977	16023
1978	16405
1979	16864
1980	17327
1981	17788
1982	18248
1983	18703
1984	19146
1985	19570
1986	19969
1987	20353
1988	20718
1989	21055
1990	21368
1991	21655
1992	22049
1993	22574
1994	22997
1995	23055
1996	22832
1997	22582
1998	22341
1999	22067
2000	21776
2001	21519
2002	21272
2003	21027
2004	20761
2005	20485
2006	20190
2007	19828
2008	19452
2009	19120
2010	18819
2011	18603
2012	18414
2013	18162
2014	17938
2015	17748
2016	17608
2017	17497
2018	17350
2019	17193
2020	17034
2021	16888
2022	16793
2023	16719