Year	Percent
1990	18.25925
1991	19.57735
1992	18.4816
1993	18.70559
1994	19.77008
1995	19.22124
1996	19.95481
1997	20.56489
1998	21.17423
1999	20.69309
2000	21.27375
2001	20.80511
2002	21.87741
2003	20.94987
2004	20.64119
2005	20.771
2006	21.92824
2007	22.87495
2008	23.85714
2009	23.7398
2010	22.91477
2011	22.57613
2012	23.01422
2013	21.60134
2014	23.86168