Year	Number
1960	43752
1961	44268
1962	44912
1963	45410
1964	45824
1965	46067
1966	46081
1967	45941
1968	45646
1969	45197
1970	44602
1971	43880
1972	43062
1973	42177
1974	41230
1975	40224
1976	39189
1977	38191
1978	37300
1979	36531
1980	35857
1981	35271
1982	34792
1983	34412
1984	34093
1985	33785
1986	33428
1987	32997
1988	32499
1989	31993
1990	31522
1991	31116
1992	30812
1993	30581
1994	30376
1995	30189
1996	30009
1997	29794
1998	29543
1999	29345
2000	29158
2001	28959
2002	28825
2003	28711
2004	28539
2005	28291
2006	28014
2007	27825
2008	27852
2009	27970
2010	27961
2011	27826
2012	27618
2013	27338
2014	26988
2015	26567
2016	26124
2017	25721
2018	25367
2019	25054
2020	24798
2021	24565
2022	24259
2023	23836