Year	Number
1973	20329
1974	18158
1975	16657
1976	15479
1977	14537
1978	13664
1979	12906
1980	12382
1981	11837
1982	11130
1983	10358
1984	9644
1985	9117
1986	8798
1987	8579
1988	8335
1989	7987
1990	7571
1991	6974
1992	6323
1993	5835
1994	5378
1995	4988
1996	4791
1997	4686
1998	4503
1999	4285
2000	4111
2001	3908
2002	3695
2003	3526
2004	3390
2005	3248
2006	3097
2007	3008
2008	2946
2009	2850
2010	2790
2011	2760
2012	2735
2013	2734
2014	2774
2015	2840
2016	2931
2017	2981
2018	2946
2019	2893
2020	2823
2021	2768
2022	2726