Year	Number
1970	42172
1971	45212
1972	45579
1973	46070
1974	44325
1975	41135
1976	39018
1977	36871
1978	37234
1979	36894
1980	34013
1981	29727
1983	27112
1984	27221
1985	25495
1986	24146
1987	23725
1988	24130
1989	23661
1990	25479
1991	23378
1992	24087
1993	24149
1994	23612
1995	34811
1996	32943
1998	27487
1999	27958
2000	26417
2001	24044
2002	23550
2003	23738
2004	20211
2005	23687
2006	21223
2007	22301
2008	22992
2009	21319
2012	11937
2013	10690
2014	17698