Year	%
1988	6.91
1989	7.73
1990	10.39
1991	12.2
1992	9.3
1993	8.8
1994	9.41
1995	8.14
1996	8.62
1997	7.67
1998	7.71
1999	9.31
2000	8.48
2001	8.53
2002	7.57
2003	6.68
2004	6.59
2005	6.61
2006	7.05
2007	6.77
2008	6.45
2009	6.36
2010	7.54
2011	7.45
2012	6.71
2013	7.61
2014	7.22
2015	7.14
2016	7.56
2017	6.85