Year	Percent
1991	9.502
1992	10.868
1993	8.496
1994	10.515
1995	8.694
1996	7.797
1997	7.553
1998	7.589
1999	7.538
2000	7.458
2001	7.385
2002	7.904
2003	8.338
2004	7.744
2005	7.666
2006	8.498
2007	9.092
2008	8.08
2009	7.593
2010	7.239
2011	6.714
2012	6.475
2013	6.541
2014	6.433
2015	6.558
2016	6.649
2017	6.705
2018	6.693
2019	6.636
2020	6.563
2021	6.465
2022	6.39