Year	Percent
1968	6.44978
1969	7.09072
1970	6.46535
1971	6.31666
1972	5.90745
1973	6.01504
1974	4.86876
1975	5.54607
1976	5.14537
1977	5.55932
1978	5.70821
1979	5.35225
1980	5.29746
1981	5.42481
1982	5.71285
1983	6.118
1984	4.95325
1985	5.60676
1986	6.42009
1987	5.91573
1988	6.41382
1989	5.89726
1990	5.21214
1991	5.29186
1992	5.13763
1993	5.17534
1994	4.87994
1995	5.04047
1996	4.08962
1997	4.49549
1998	4.95043
1999	4.35106
2000	3.93299
2001	4.23151
2002	3.84705
2003	4.31315
2004	3.71882
2005	3.69518
2006	3.6568
2007	3.81354
2008	4.15842
2009	5.66218
2010	5.37527
2011	5.01293
2012	5.01637
2013	4.90255
2014	5.02675