Year	Percent
1992	31.50912
1993	20.02508
1994	28.70407
1995	19.88853
1996	20.52549
1997	19.62816
1998	20.46086
1999	13.70423
2000	18.13905
2001	26.87642
2002	27.28772
2003	25.70391
2004	26.31109
2005	30.96977
2006	33.90079
2007	35.5267
2008	27.50648
2009	29.41456
2010	25.37355
2011	22.99815
2012	25.22966
2013	24.56961
2014	25.79025
2015	27.90792
2016	27.82758