Year	Percent
1991	35.31191
1992	35.22044
1993	34.95096
1994	34.67697
1995	34.26051
1996	34.1166
1997	33.83709
1998	33.78818
1999	33.75202
2000	33.89756
2001	34.00225
2002	33.82805
2003	31.32631
2004	32.75005
2005	32.01626
2006	30.30913
2007	28.66883
2008	25.29625
2009	27.95723
2010	25.62074
2011	25.51703
2012	26.1407
2013	22.82328
2014	22.08362
2015	19.70199
2016	21.32412
2017	20.17781
2018	20.07671
2019	18.70298