Year	Percent
1991	4.322
1992	4.308
1993	4.299
1994	4.279
1995	4.305
1996	3.964
1997	3.884
1998	4.445
1999	4.667
2000	4.741
2001	4.267
2002	3.769
2003	4.148
2004	4.215
2005	4.197
2006	4.487
2007	5.163
2008	5.129
2009	5.005
2010	4.154
2011	4.454
2012	3.533
2013	3.074
2014	3.789
2015	4.589
2016	3.837
2017	3.537
2018	3.832
2019	4.021
2020	4.183
2021	4.32
2022	4.432