Year	Number
1960	29872
1961	30382
1962	30930
1963	31517
1964	32148
1965	32891
1966	33718
1967	34577
1968	35405
1969	36051
1970	36476
1971	36518
1972	36335
1973	36137
1974	36023
1975	36258
1976	36884
1977	37798
1978	38869
1979	39987
1980	41129
1981	42325
1982	43911
1983	45894
1984	48332
1985	51111
1986	54002
1987	56790
1988	59310
1989	61611
1990	63615
1991	65374
1992	66853
1993	67869
1994	68399
1995	68658
1996	68890
1997	69106
1998	69226
1999	69017
2000	67833
2001	65187
2002	61663
2003	58140
2004	54684
2005	51720
2006	49303
2007	47857
2008	46555
2009	44959
2010	43524
2011	43260
2012	42901
2013	42022
2014	41121
2015	40943
2016	39673
2017	39456
2018	40102
2019	39602
2020	38252
2021	37473
2022	37015