Year	Number
1973	23908
1974	24290
1975	24642
1976	24990
1977	25262
1978	25456
1979	25637
1980	26014
1981	25341
1982	24830
1983	26887
1984	28932
1985	28786
1986	28495
1987	29496
1988	30924
1989	32085
1990	33034
1991	33524
1992	34762
1993	36361
1994	36358
1995	36338
1996	37983
1997	39355
1998	39972
1999	40546
2000	41044
2001	41602
2002	41934
2003	42294
2004	43357
2005	44770
2006	45617
2007	46146
2008	46519
2009	46829
2010	47322
2011	47679
2012	48011
2013	48215
2014	48447
2015	48599
2016	48286
2017	47899
2018	47725
2019	47911
2020	48043
2021	47942
2022	47919