Year	Number of
1981	0
1989	0.01514
1992	0.02839
1995	0.01773
1996	0.02208
1997	0.01995
1998	0.02666
2000	0.01594
2001	0.02029
2002	0.02629
2003	0.03159
2004	0.03955
2005	0.04356
2006	0.02431
2007	0.01602
2008	0.00871
2009	0.00907
2010	0.00674
2011	0.00846
2012	0.01053