Year	Percent
1990	6.44
1991	6.08
1992	5.45
1993	5.28
1994	6.07
1995	5.91
1996	6.59
1997	6.16
1998	5.95
1999	7.13
2000	7.65
2001	8.58
2002	9.55
2003	9.85
2004	11.27
2005	11.75
2006	12.86
2007	14.19
2008	15.4
2009	15.91
2010	17
2011	18.95
2012	19.89
2013	20.67
2014	21.26
2015	21.97
2016	23.3
2017	24.18
2018	24.1
2019	24.13