Year	Number
1975	13397
1976	13060
1977	13076
1978	13242
1979	13803
1980	14233
1981	14636
1982	14829
1983	15117
1984	15484
1985	15521
1986	15674
1987	15852
1988	15880
1989	15393
1990	15513
1991	15614
1992	15775
1993	16212
1994	16212
1995	16339
1996	16311
1997	16202
1998	18002
1999	21148
2001	21865
2002	22979
2003	23972
2004	24792
2005	25416
2006	26833
2007	29852
2008	30697
2009	31549
2010	32043
2011	32848
2012	32267
2021	39152