Year	Percent
1990	1.66661
1991	1.65823
1992	1.92362
1993	2.31987
1994	2.94399
1995	2.63496
1996	2.76305
1997	2.97486
1998	2.78406
1999	2.49303
2000	2.18484
2001	1.76127
2002	1.77488
2003	1.87634
2004	2.15049
2005	2.08799
2006	2.17539
2007	1.91201
2008	1.72707
2009	2.22853
2010	2.46689
2011	2.34819
2012	2.59862
2013	2.7784
2014	3.14484
2015	3.23028
2016	3.07829
2017	2.81837