Year	Percent
1991	4.44236
1992	4.36402
1993	4.28767
1994	4.15394
1995	4.01562
1996	3.88012
1997	3.70328
1998	3.30186
1999	2.93639
2000	2.6008
2001	2.29691
2002	2.4445
2003	2.59984
2004	2.75204
2005	2.86284
2006	2.97085
2007	2.35424
2008	1.57009
2009	1.57014
2010	1.46382
2011	1.35986
2012	1.35016
2013	1.38223
2014	1.30622
2015	1.23001
2016	1.21989
2017	1.24988
2018	1.21016
2019	1.16835