Year	Percent
1990	3.566
1991	3.47419
1992	3.5042
1993	3.42198
1994	4.51172
1995	5.52108
1996	5.81953
1997	6.17983
1998	5.57874
1999	6.43155
2000	5.91983
2001	6.39747
2002	6.25082
2003	6.12216
2004	5.97263
2005	5.85435
2006	5.12546
2007	5.00988
2008	4.83999
2009	4.88682
2010	4.76488
2011	4.69988
2012	4.51368
2013	4.06081
2014	3.62875
2015	3.53565
2016	3.615
2017	3.70348
2018	3.80179
2019	3.91068
2020	4.39021