Year	Percent
1979-01-01	6.32756846666667
1980-01-01	6.17087134166667
1981-01-01	5.83928689166667
1982-01-01	7.22809951666667
1983-01-01	10.05842065833330
1984-01-01	9.07672443333334
1985-01-01	8.33885076666667
1986-01-01	8.15736234166667
1987-01-01	8.19143817500000
1988-01-01	7.30160289166667
1989-01-01	6.23401111666667
1990-01-01	6.98726073333333
1991-01-01	9.67144751666666
1992-01-01	10.83433515000000
1993-01-01	10.97598200833330
1994-01-01	9.82320374166667
1995-01-01	8.56635960833333
1996-01-01	8.59915190833333
1997-01-01	8.46091788333334
1998-01-01	7.77447285000000
1999-01-01	6.96068165833333
2000-01-01	6.36603576666667
2001-01-01	6.82471905000000
2002-01-01	6.45799270000000
2003-01-01	6.00995468333333
2004-01-01	5.47194375833333
2005-01-01	5.10985773333333
2006-01-01	4.85419860000000
2007-01-01	4.45137105833333
2008-01-01	4.31162873333333
2009-01-01	5.67407570833333
2010-01-01	5.31792657500000
2011-01-01	5.19969300000000
2012-01-01	5.34390210000000
2013-01-01	5.80518230000000
2014-01-01	6.21690905833333
2015-01-01	6.22107981666667
2016-01-01	5.86865157500000
2017-01-01	5.76163932500000