Year	Percent
1991	27.88618
1992	29.53414
1993	30.98071
1994	29.74545
1995	28.38
1996	28.30009
1997	28.28649
1998	27.98515
1999	27.84
2000	32.89455
2001	31.01678
2002	28.92759
2003	26.98
2004	24.97883
2005	22.92742
2006	20.99392
2007	19.14
2008	17.55296
2009	15.99504
2010	14.51245
2011	13.23086
2012	13.20717
2013	13.15668
2014	12.82712
2015	12.26722
2016	11.7316
2017	11.21531
2018	10.65711
2019	10.12413