Year	Percent
1991	5.564
1992	5.939
1993	6.245
1994	5.692
1995	5.449
1996	4.842
1997	4.318
1998	4.154
1999	3.901
2000	3.801
2001	3.381
2002	3.457
2003	3.214
2004	3.035
2005	2.823
2006	2.794
2007	2.532
2008	2.305
2009	2.221
2010	1.917
2011	1.874
2012	1.927
2013	2.067
2014	1.637
2015	1.637
2016	1.72
2017	1.682
2018	1.606
2019	1.551
2020	1.509
2021	1.471
2022	1.437