Year	%
1995	30.77
1996	30.23
1997	30.64
1998	30.23
1999	27.61
2000	27.59
2001	24.77
2002	27.8
2003	28.73
2004	28.45
2005	26.33
2006	32.72
2007	30.9
2008	31.02
2009	24.34
2010	29.97
2011	30.71
2012	28.49
2013	32.47
2014	17.44
2015	28.53
2016	27.06
2017	29.18