Year	Percent
1991	6.065
1992	6.053
1993	3.944
1994	3.04
1995	2.758
1996	2.96
1997	3.084
1998	3.238
1999	3.637
2000	3.926
2001	4.059
2002	4.048
2003	3.838
2004	3.602
2005	3.629
2006	3.423
2007	3.366
2008	3.437
2009	3.862
2010	4.314
2011	4.251
2012	4.255
2013	4.398
2014	4.569
2015	4.632
2016	4.808
2017	4.857
2018	4.888
2019	4.643
2020	4.549
2021	4.432
2022	4.338