Year	Percent
1991	3.318
1992	3.366
1993	3.183
1994	3.11
1995	2.878
1996	2.86
1997	2.794
1998	3.084
1999	2.909
2000	2.86
2001	2.777
2002	2.796
2003	2.814
2004	2.79
2005	2.674
2006	2.774
2007	2.945
2008	2.958
2009	2.822
2010	2.917
2011	3.177
2012	3.159
2013	3.13
2014	3.115
2015	2.922
2016	2.602
2017	2.626
2018	2.626
2019	2.625
2020	2.601
2021	2.6
2022	2.594