Year	Percent
1991	25.11253
1992	25.40804
1993	25.79623
1994	26.16701
1995	26.47952
1996	26.79597
1997	26.72036
1998	26.84705
1999	26.94409
2000	26.49467
2001	25.96458
2002	25.46813
2003	24.68809
2004	23.93546
2005	23.33666
2006	22.56103
2007	21.89093
2008	21.38395
2009	21.30143
2010	20.32793
2011	20.34297
2012	19.89079
2013	20.00947
2014	14.76722
2015	15.25868
2016	15.59838
2017	15.40678
2018	14.42125
2019	13.81623