Year	Percent
1990	7.6
1991	8.37
1992	8
1993	7.18
1994	6.48
1995	6.13
1996	4.42
1997	4.62
1998	5.05
1999	5.53
2000	6.05
2001	6.6
2002	7.2
2003	7.85
2004	7.99
2005	8.41
2006	8.85
2007	9.32
2008	9.81
2009	10.34
2010	10.44
2011	10.59
2012	10.29
2013	12.97
2014	9.79
2015	11.48
2016	13.77
2017	13.91
2018	14.03
2019	14.18