Year	Percent
1991	3.861
1992	3.585
1993	4.07
1994	4.441
1995	4.601
1996	4.722
1997	4.865
1998	4.778
1999	4.548
2000	5.129
2001	5.131
2002	5.178
2003	5.187
2004	5.181
2005	4.737
2006	4.564
2007	4.601
2008	4.376
2009	4.679
2010	4.514
2011	4.721
2012	4.803
2013	4.808
2014	4.916
2015	5.004
2016	5.116
2017	5.153
2018	5.207
2019	5.28
2020	5.355
2021	5.434
2022	5.53