Year	Number of
1986	1.091
1989	0.8632
1992	0.3514
1996	0.3808
1997	0.4087
2000	0.454
2001	0.3238
2002	0.4709
2003	0.5833
2004	0.7209
2005	0.5027
2006	0.401
2007	0.3577
2008	0.3266
2009	0.2955
2010	0.2244
2011	0.2577
2012	0.2312