Year	Percent
1995	67.3
1996	69.81
1997	67.93
1998	71.6
1999	68.51
2000	72.36
2001	68.28
2002	67.04
2003	56.75
2004	57.62
2005	51.15
2006	50.41
2007	47.7
2008	39.17
2009	35.82
2010	35.91