Year	Number
1989	6.66086
1990	6.62961
1991	6.56673
1992	6.36675
1993	6.58335
1994	7.0087
1995	6.81651
1996	6.75624
1997	6.42813
1998	6.92531
1999	7.9415
2000	7.84027
2001	7.98738
2003	7.58219
2004	7.535
2005	7.46564
2006	7.52136
2008	7.26147
2009	5.92078
2010	5.66671
2011	6.36712
2012	6.8194