Year	Percent
1990	19.02083
1991	18.3048
1992	17.95346
1993	17.47
1994	17.16798
1995	17.75202
1996	16.95069
1997	16.00769
1998	14.47643
1999	15.01208
2000	14.50277
2001	14.6255
2002	14.02036
2003	12.71068
2004	13.46597
2005	13.73253
2006	14.57726
2007	14.22161
2008	13.27733
2009	12.80032
2010	11.30003
2011	11.25639
2012	10.40842
2013	10.48662
2014	10.13751
2015	12.37995
2016	12.29293