Year	Percent
1990	24.89
1991	24.98
1992	25.11
1993	25.22
1994	25.35
1995	25.49
1996	25.65
1997	25.79
1998	25.88
1999	25.94
2000	26.03
2001	26.12
2002	26.2
2003	26.29
2004	26.38
2005	26.46
2006	26.56
2007	26.65
2008	26.71
2009	26.77
2010	27.4
2011	27.77
2012	27.55
2013	28.69
2014	28.6
2015	30.72
2016	29.71
2017	27.55
2018	24.91
2019	24.99