Year	Percent
1969	11.2
1970	2.369
1971	4.943
1972	3.003
1973	3.587
1974	8.302
1975	1.088
1976	5.096
1977	4.41
1978	9.221
1979	3.584
1980	10.77
1981	8.015
1982	1.811
1983	4.642
1985	1.168
1987	5.177
1988	4.74
1989	10.51
1990	15.56
1991	20.49
1992	37.05
1993	24.21
1994	28.12
1995	30.53
1996	23.22
1998	28.13
1999	32.52
2000	46.39
2001	46.07
2002	42.08
2003	32.66
2004	30.38
2005	29.36
2006	28.17
2007	21.83