Year	Number
1970	41529
1972	41529
1975	49182
1976	46885
1977	45428
1978	41730
1979	38815
1980	33350
1981	28602
1982	17444
1983	27662
1984	29827
1985	31286
1986	35313
1987	34600
1988	30695
1989	26394
1990	20567
1991	14701
1992	11523
1993	10588
1994	30612
1996	20228
1999	12590
2000	10243
2001	9984
2002	16716
2003	19878
2004	22663
2005	20938
2006	27783
2007	34776
2008	40219
2009	44206
2010	41988
2011	41534
2012	42943