Year	Percent
1990	26.26584
1991	18.23937
1992	19.84951
1993	18.98088
1994	8.99367
1995	9.40273
1996	9.49444
1997	10.58909
1998	11.03648
1999	10.71895
2000	10.64687
2001	9.80251
2002	10.3955
2003	11.72082
2004	12.18818
2005	12.8998
2006	13.68421
2007	13.86209
2008	13.20168
2009	13.13766
2010	13.67837
2011	14.5197
2012	15.00914
2013	15.02043
2014	15.31623
2015	15.7696
2016	16.29122