Year	Percent
1990	3.62
1991	3.2
1992	3.3
1993	3.22
1994	3.15
1995	2.82
1996	2.99
1997	3.06
1998	2.74
1999	2.63
2000	2.6
2001	3.31
2002	4.06
2003	3.56
2004	4.67
2005	4.88
2006	5.42
2007	5.68
2008	6.06
2009	6.94
2010	5.97
2011	5.64
2012	6.64
2013	6.87
2014	7.65
2015	7.25
2016	7
2017	7.66
2018	8.33
2019	9.35