Year	Percent
1972	0.1486
1973	3.231
1974	0.6995
1975	2.986
1976	2.944
1977	2.796
1978	4.579
1979	1.768
1980	2.806
1981	8.562
1982	4.557
1983	3.066
1984	1.1
1986	0.2322
1987	5.52
1988	6.624
1989	3.703
1990	1.916
1991	6.917
1992	7.54
1993	7.161
1994	2.088
1995	3.134
1996	7.442
1997	13.67
1998	15.41
1999	13.08
2000	17.05
2001	16.45
2002	17.6
2003	17.44
2004	15.16
2005	32.54
2006	9.485
2007	10.87