Year	Percent
1990	3.33295
1991	3.23192
1992	2.90763
1993	2.77276
1994	1.83873
1995	3.37203
1996	3.32228
1997	3.24728
1998	3.15959
1999	3.06889
2000	2.98317
2001	2.90496
2002	2.86956
2003	2.8184
2004	2.67315
2005	2.75381
2006	2.69996
2007	2.64449
2008	2.5833
2009	2.50523
2010	2.4488
2011	2.3951
2012	2.34786
2013	2.31264
2014	2.27247
2015	2.2323
2016	2.19185
2017	2.16665
2018	2.08823
2019	2.0408
2020	1.99576