Year	Percent
1976	1.9
1977	1.37
1978	2.89
1980	1.37
1982	2.57
1985	2.15
1986	2.61
1987	2.63
1988	2.76
1990	2.43
1991	2.32
1992	2.59
1996	3.71
1998	5.04
1999	5.96
2000	5.6834
2001	5.3043
2002	5.8853
2003	5.7073
2004	6.2444
2005	6.7817
2006	6.5854
2007	6.9498
2008	6.6573
2009	5.7392
2010	5.128
2011	4.8989
2012	4.2722
2013	4.3786
2014	4.1502
2015	4.566
2016	4.5729
2017	4.3529