Year	Percent
1991	6.185
1992	6.371
1993	6.497
1994	6.756
1995	9.27
1996	8.097
1997	6.712
1998	6.555
1999	6.761
2000	6.575
2001	6.524
2002	6.551
2003	6.779
2004	6.784
2005	6.653
2006	6.725
2007	6.683
2008	6.55
2009	6.393
2010	6.021
2011	6.4
2012	6.615
2013	6.485
2014	6.515
2015	6.678
2016	6.794
2017	6.765
2018	6.893
2019	6.931
2020	6.847
2021	6.76
2022	6.665