Year	Percent
1982	5.4
1983	4.8
1984	4.19
1987	6.6
1988	7.2
1989	7.8
1990	6.93
1991	5.85
1992	6.73
1993	12.7
1994	14.06
1995	22.3
1996	19.31
1997	17.8
1998	14.11
1999	15.18
2000	16.38
2001	17.19
2002	18.83
2003	17.48
2004	15.7447
2005	13.5213
2006	12.3408
2008	9.6801
2009	9.8313
2010	9.1689
2011	8.4851
2012	8.7876
2013	8.4641
2014	8.3618
2017	9.4463