Year	Percent
1995	19.61468
1996	18.86539
1997	17.93411
1998	18.20056
1999	19.12695
2000	18.7476
2001	19.33277
2002	19.43872
2003	20.51752
2004	20.34402
2005	17.80449
2006	19.98724
2007	17.99836
2008	15.65978
2009	15.31347
2010	13.82784
2011	13.68227
2012	14.32591
2013	14.66414
2014	14.14761
2015	13.7964
2016	14.23399
2017	14.7869