Year	Percent
1991	13.085
1992	11.608
1993	11.604
1994	11.59
1995	12.448
1996	11.733
1997	9.888
1998	8.327
1999	7.436
2000	6.181
2001	6.075
2002	6.425
2003	6.253
2004	5.356
2005	5.205
2006	4.6
2007	5.934
2008	5.771
2009	7.997
2010	6.775
2011	6.436
2012	6.44
2013	5.788
2014	5.815
2015	5.843
2016	5.748
2017	5.764
2018	5.713
2019	5.683
2020	5.647
2021	5.657
2022	5.614