Year	Percent
1978	0.02094
1979	0.01751
1980	0.53554
1981	1.41533
1982	7.48506
1983	7.65969
1991	6.65088
1992	6.76003
1993	6.15874
1994	5.75744
1995	5.79165
1996	5.08048
1997	5.47499
1998	5.65087
1999	5.47809
2000	5.0691
2004	5.60718
2005	6.32684
2006	6.43261
2007	4.06183
2008	3.72902