Year	Percent
1991	5.653
1992	5.644
1993	5.643
1994	5.639
1995	5.612
1996	5.606
1997	5.656
1998	5.727
1999	5.686
2000	5.764
2001	5.688
2002	5.676
2003	5.752
2004	9.278
2005	9.963
2006	10.282
2007	9.912
2008	10.508
2009	8.816
2010	9.271
2011	10.295
2012	10.117
2013	9.556
2014	9.129
2015	8.291
2016	7.986
2017	7.974
2018	7.973
2019	7.972
2020	7.969
2021	7.967
2022	7.965
