Year	Percent
1991	29.72611
1992	29.78448
1993	29.54828
1994	29.41247
1995	29.33692
1996	29.3661
1997	29.10218
1998	29.07591
1999	29.53553
2000	29.834
2001	29.64536
2002	29.71334
2003	29.7973
2004	30.4431
2005	30.34599
2006	29.62041
2007	28.48733
2008	27.9548
2009	28.53463
2010	27.87781
2011	27.90551
2012	27.98121
2013	26.64963
2014	25.2804
2015	26.19158
2016	26.94193
2017	27.69388
2018	28.82471
2019	29.73769