Year	Percent
1973	7.228
1974	10.46
1975	4.835
1976	10.71
1977	6.878
1978	4.748
1979	2.519
1980	1.125
1981	3.867
1982	8.348
1983	6.576
1984	6.999
1985	4.595
1986	19.12
1987	13.99
1988	4.021
1991	7.566
1992	7.439
1993	3.364
1994	3.292
1995	3.298
1999	9.547
2000	11.53
2001	16.4
2002	15.81
2003	15
2004	21.89
2005	23.85
2006	21.47
2007	26.64