Year	Percent
1973	6.979
1974	10.73
1975	5.199
1976	0.778
1977	9.781
1978	7.49
1979	2.247
1980	9.871
1981	6.146
1982	1.897
1983	3.682
1984	2.72
1985	1.455
1987	3.076
1988	2.16
1991	3.592
1992	3.912
1993	2.546
1994	3.099
1995	3.104
1998	7.381
1999	6.217
2000	5.649
2001	5.956
2002	5.536
2003	9.263
2004	8.323
2005	11.52
2006	9.244
2007	5.965