Year	Number
1970	45835
1971	45378
1972	44570
1973	43735
1974	42935
1975	42029
1976	41852
1977	41530
1978	40500
1979	39573
1980	38747
1981	37016
1982	34587
1983	31623
1984	28701
1985	26133
1986	23627
1987	21835
1988	20511
1989	19718
1990	18967
1991	18843
1992	18908
1993	18551
1994	18054
1995	16687
1996	15473
1997	14489
1998	13760
1999	13523
2000	13411
2001	13272
2002	13194
2003	13461
2004	13647
2005	13854
2006	14056
2007	14413
2008	14787
2009	15189
2010	15520
2011	15791
2012	16053
2013	15755
2014	15595
2015	15432
2016	15396
2017	15681
2018	15966
2019	15958
2020	15512
2021	14813
2022	14010