Year	Number
1960	23960
1961	25266
1962	26651
1963	28063
1964	29423
1965	30790
1966	32329
1967	34056
1968	35917
1969	37717
1970	38889
1971	39503
1972	40051
1973	40522
1974	40825
1975	40878
1976	40747
1977	40549
1978	40296
1979	39995
1980	39685
1981	39547
1982	39634
1983	39842
1984	40227
1985	40763
1986	41300
1987	41766
1988	42225
1989	42801
1990	43403
1991	44002
1992	44822
1993	45822
1994	46674
1995	47314
1996	47811
1997	48243
1998	48671
1999	48895
2000	48900
2001	48846
2002	48857
2003	48887
2004	48849
2005	48829
2006	48845
2007	48828
2008	48839
2009	49038
2010	48959
2011	48416
2012	47832
2013	47096
2014	46329
2015	45628
2016	44823
2017	43960
2018	43068
2019	42138
2020	41175
2021	40248
2022	39380
2023	38542