Year	Percent
1990	2.82
1991	3.05
1992	3.19
1993	3.2
1994	3.18
1995	3.08
1996	3.01
1997	3.04
1998	2.97
1999	3.13
2000	3.08
2001	3.08
2002	3.06
2003	3.03
2004	2.96
2005	2.9
2006	2.79
2007	2.71
2008	2.64
2009	2.69
2010	2.65
2011	2.62
2012	3.15
2013	2.74
2014	4.1
2015	6.14
2016	6.45
2017	6.98
2018	8.29
2019	8.92