Year	Percent
1990	24.38
1991	25.25
1992	25.42
1993	24.83
1994	24.77
1995	24.5
1996	24.17
1997	24.19
1998	23.77
1999	23.45
2000	22.59
2001	21.76
2002	20.69
2003	20.09
2004	19.75
2005	19.73
2006	19.84
2007	20.05
2008	20.13
2009	20.02
2010	19.89
2011	19.93
2012	19.96
2013	20.51
2014	21.27
2015	22.13
2016	22.75
2017	23.45
2018	24.69
2019	25.32