Year	Percent
1996	19.378
1997	19.75337
1998	16.7301
1999	14.09361
2000	13.66691
2001	17.79489
2002	17.447
2003	15.49566
2004	15.19906
2005	14.82639
2006	14.51622
2007	14.30372
2008	14.66298
2009	14.9405
2010	13.3322
2011	14.79435
2012	15.61315
2013	15.31024
2014	14.84079
2015	14.29021
2016	13.76639