Year	Percent
1992	7.2
1999	4.35
2000	4.57
2001	4.62
2002	5.27
2003	5.56
2004	5.82
2005	6.05
2006	6.25
2007	5.73
2008	5.08
2009	5.38
2010	5.55
2011	5.77
2012	5.52
2013	5.57
2014	5.72
2015	5.59
2016	5.65
2017	5.89
2018	6.04
2020	7.45
