Year	Percent
1991	12.61395
1992	11.75381
1993	11.25156
1994	13.88219
1995	13.50372
1996	13.52173
1997	10.80611
1998	9.97811
1999	10.18883
2000	10.61066
2001	9.6493
2002	9.97393
2003	10.78378
2004	10.50121
2005	10.28533
2006	9.41756
2007	8.83651
2008	8.51775
2009	8.36821
2010	8.27958
2011	7.99385
2012	7.66378
2013	7.4482
2014	7.33629
2015	7.34796
2016	7.41539
2017	7.47184
2018	7.58391
2019	8.07144