Year	Percent
1969	4.3
1970	6.4
1971	7.5
1972	4.7
1973	4.5
1974	5.1
1975	4.81
1976	6.2
1977	5
1978	4.5
1979	3.8
1983	4.24
1984	4.7
1989	5.78
1991	6.75
1993	7.4
1994	7.5
1995	7.2
1999	7.6
2001	11.63
2002	11.68
2003	10.28
2006	8.17
2007	8.42
2008	10.94
2009	8.14
2010	8.61