Year	Percent
1996	13.20324
1997	16.07125
1998	14.33852
1999	14.31723
2000	15.0421
2001	16.51566
2002	17.35025
2003	20.17363
2004	21.38428
2005	21.09794
2006	21.25522
2007	25.60048
2008	30.39434
2009	29.45998
2010	34.53299
2011	37.56299
2012	36.93784
2013	36.37697
2014	34.80529
2015	28.94865
2016	27.628