Year	Percent
1973	0.3147
1974	0.04631
1975	2.312
1981	0.06745
1982	0.038
1983	0.05586
1984	0.2789
1985	0.2547
1986	0.2528
1987	0.3099
1988	0.00897
1989	0.2445
1990	0.4196
1991	0.2642
1992	0.6957
1993	1.29
1994	1.194
1995	4.476
1996	7.121
1997	10.8
1998	5.918
1999	8.062
2000	19.03
2001	29.11
2002	17.94
2003	20.06
2004	14.47
2005	17.17
2006	21.43
2007	18.56