Year	Number
1980	1186
1981	1987
1982	2290
1983	2238
1984	1542
1985	1681
1986	1624
1987	1651
1988	1439
1989	1708
1990	2195
1991	2533
1992	2929
1993	4573
1994	5936
1995	6184
1996	5021
1997	6145
1998	5417
1999	8723
2000	9173
2001	9858
2002	11784
2003	7468
2004	17608
2005	20440
2006	23827
2007	28604
2008	30711
2009	23465
2010	25388
2011	26825
2012	24879
2013	31732
2016	51622
2017	97236