Year	Number
1960	0
1965	0
1970	0
1975	0
1976	0
1977	0
1978	0
1979	0
1980	0
1981	0
1982	0
1983	0
1984	0
1985	0
1986	0
1987	0
1988	0
1989	0
1990	0
1991	0
1992	0
1993	0
1994	0
1995	0
1996	0
1997	0
1998	0
1999	0
2000	0
2001	0
2002	100
2003	5869
2004	12782
2005	14094
2006	18616
2007	27436
2008	27500
2009	27500
2010	27518
2011	27600
2012	31213
2013	31393
2015	22505
2016	23412
2017	23114
2019	23000
2020	22000
2021	22000