Year	Percent
1991	4.189
1992	4.695
1993	4.958
1994	5.031
1995	4.292
1996	4.12
1997	3.624
1998	3.606
1999	3.728
2000	3.379
2001	3.736
2002	3.567
2003	4.095
2004	4.603
2005	4.627
2006	4.11
2007	4.437
2008	4.131
2009	4.844
2010	5.458
2011	5.023
2012	5.854
2013	5.849
2014	5.827
2015	5.951
2016	6.022
2017	5.933
2018	5.906
2019	5.877
2020	5.862
2021	5.836
2022	5.814