Year	Percent
1990	16.67
1991	14.92
1992	14.85
1993	15.62
1994	16
1995	16.38
1996	16.35
1997	16.54
1998	16.43
1999	17.59
2000	23.04
2001	22.07
2002	19.57
2003	18.17
2004	16.79
2005	15.46
2006	14.2
2007	15.77
2008	13.48
2009	13.56
2010	14.77
2011	16.05
2012	19.33
2013	17.95
2014	15.54
2015	16.12
2016	14.51
2017	13.34
2018	12.21
2019	12.39