Year	Percent
1988	35.17442
1989	35.94203
1990	27.84636
1991	33.21006
1992	9.67543
1993	28.55486
1994	43.03635
1995	65.58544
1996	76.58832
1997	87.23828
1998	48.91504
1999	66.07338
2000	98.7622
2001	67.99196
2002	65.46116
2003	63.37686
2004	58.31411
2005	26.99433
2006	23.19123
2007	20.61299
2008	16.75817
2009	15.17025
2010	14.93735
2011	16.44713
2012	17.18664
2013	11.28736
2014	9.05404
2015	10.50394
2016	13.27674
2017	15.70979