Year	Percent
1996	10.65
1997	12.67
1998	11.58
1999	12
2000	12.44
2001	13.89
2002	14.7
2003	16.41
2004	17.35
2006	20.18
2007	20.38
2009	21.84
2010	21.56
2011	21.27
2012	21.18
2013	21.18
2014	21.43
2015	22.74
2016	24.76
2017	25.78