Year	Percent
1991	11.73074
1992	11.54246
1993	11.5632
1994	11.76441
1995	11.48188
1996	12.2034
1997	13.28509
1998	13.93148
1999	12.7932
2000	12.68101
2001	13.17029
2002	12.62501
2003	12.97321
2004	12.29691
2005	12.05128
2006	11.90859
2007	11.84168
2008	11.4398
2009	11.4471
2010	11.1983
2011	10.20958
2012	10.8073
2013	10.22951
2014	8.64748
2015	7.5302
2016	6.91329
2017	6.40029
2018	6.04441
2019	5.49445