Year	Percent
1990	9.95
1991	10.23
1992	10.48
1993	10.73
1994	11.07
1995	11.49
1996	11.79
1997	12.06
1998	12.18
1999	12.34
2000	12.15
2001	12.01
2002	11.4
2003	11.27
2004	10.51
2005	11.79
2006	13.21
2007	14.78
2008	15.98
2009	17.07
2010	17.57
2011	20.36
2012	22.07
2013	23.82
2014	24.8
2015	25.84
2016	26.64
2017	26.94
2018	28.13
2019	28.57