Year	Number
1975	45136
1976	45024
1977	45108
1978	45599
1979	45967
1980	46194
1981	46969
1982	47494
1983	47851
1984	48005
1985	48032
1986	48024
1987	47504
1988	46924
1989	46205
1990	45229
1991	43846
1992	41792
1993	39190
1994	35964
1995	32349
1996	29079
1997	26302
1998	23958
1999	22368
2000	21419
2001	20554
2002	20105
2003	19285
2004	18873
2005	18208
2006	17545
2007	17528
2008	17563
2009	17429
2010	17359
2011	17407
2012	17585
2013	17686
2014	17526
2015	17358
2016	16997
2017	16651
2018	16396
2019	16167
2020	15884
2021	15424
2022	14977