Year	%
1988	6.31
1989	9.58
1990	7.32
1991	10.65
1992	11.71
1993	14.92
1994	12.96
1995	6.64
1996	7.3
1997	6.31
1998	5.86
1999	6.58
2000	5.72
2001	6.34
2002	5.03
2003	5.03
2004	4.46
2005	3.94
2006	3.64
2007	3.92
2008	3.81
2009	3.57
2010	3.87
2011	4.48
2012	3.04
2013	3.14
2014	4
2015	4.28
2016	3.71
2017	3.88