Year	Percent
1988	6.803
1989	6.90692
1990	6.71763
1991	7.80973
1992	7.44537
1993	8.30975
1994	8.40185
1995	7.27112
1996	7.60406
1997	7.00884
1998	6.95735
1999	7.86561
2000	7.98652
2001	7.7653
2002	7.21659
2003	7.489
2004	7.25923
2005	7.26109
2006	6.38245
2007	5.10733
2008	5.30599
2009	6.23128
2010	6.35735
2011	6.46723
2012	6.99275
2013	7.66621
2014	6.99704
2015	7.1461
2016	6.97988