Year	Percent
1991	4.012
1992	4.374
1993	3.977
1994	4.312
1995	4.291
1996	4.026
1997	4.676
1998	4.606
1999	4.788
2000	4.68
2001	4.736
2002	4.821
2003	4.955
2004	4.794
2005	4.64
2006	4.63
2007	4.512
2008	4.444
2009	4.444
2010	4.3
2011	4.167
2012	4.445
2013	4.56
2014	4.75
2015	4.632
2016	4.597
2017	4.556
2018	4.488
2019	4.421
2020	4.35
2021	4.286
2022	4.227