Year	Percent
1992	10.573
1993	11.184
1994	11.304
1995	10.395
1996	9.33
1997	8.315
1998	7.2399
1999	9.8614
2000	12.2937
2001	14.2053
2002	16.5461
2003	16.2782
2004	16.1162
2005	14.2554
2006	11.1952
2007	7.7484
2008	5.4025
2009	6.3403
2010	7.9186
2011	7.4935
2012	7.957
2013	8.1836
2014	7.2222
2015	6.2223
2016	5.1426
2017	4.072