Year	Percent
1991	22.49236
1992	21.78919
1993	21.10703
1994	20.55697
1995	19.96934
1996	19.36155
1997	17.29133
1998	18.79922
1999	18.3691
2000	18.36124
2001	15.12953
2002	14.92958
2003	14.26969
2004	14.55835
2005	14.64142
2006	14.63017
2007	14.7329
2008	13.96187
2009	13.50065
2010	13.29963
2011	11.88081
2012	13.25609
2013	12.69112
2014	12.591
2015	12.47341
2016	11.36984
2017	11.27814
2018	10.61279
2019	10.26189