Year	Percent
1978	5.37094
1979	13.34728
1980	10.57612
1981	20.53983
1982	19.98572
1983	28.6659
1984	26.64663
1985	34.404
1986	46.23553
1987	45.03459
1988	46.06878
1989	27.92686
1990	34.57177
1991	26.26409
1992	14.71616
1993	13.33991
1994	54.12998
1995	13.49289
1996	20.74443
1997	7.68313
1998	3.06832
1999	1.5394
2000	1.70471
2001	4.24493
2002	1.21267
2003	2.28584
2004	5.8256
2005	2.25489
2006	1.3802
2007	1.76182