Year	Number
1980	126554
1981	108901
1982	99661
1983	96993
1984	121835
1985	99099
1986	195726
1987	229514
1988	187892
1989	200219
1990	224106
1991	205192
1992	203371
1993	232671
1994	234111
1995	254154
1996	260734
1997	287360
1998	274097
1999	292113
2000	361246
2001	303685
2002	309477
2003	345322
2004	353024
2005	389907
2006	397533
2007	419985
2008	440591
2009	406474
2010	462798
2011	445025
2012	445069
2013	469460
2014	476342
2015	489495
2016	516873
2017	560016