Year	Percent
1974	0.751
1975	5.735
1976	0.5419
1977	0.5769
1978	0.212
1979	11.03
1980	7.012
1981	4.459
1982	2.901
1983	7.069
1984	5.369
1985	4.881
1986	0.08798
1987	0.5156
1988	0.2751
1991	6.886
1992	5.909
1993	11.55
1994	6.626
1995	6.621
1999	10.05
2000	9.227
2001	9.287
2002	9.095
2003	7.788
2004	8.096
2005	7.06
2006	6.273
2007	8.611