Year	Percent
1973-01-01	10.884900000000000
1974-01-01	13.106600000000000
1975-01-01	12.347100000000000
1976-01-01	10.976400000000000
1977-01-01	12.856800000000000
1978-01-01	13.806200000000000
1979-01-01	13.406300000000000
1980-01-01	14.141100000000000
1981-01-01	13.963200000000000
1982-01-01	13.901300000000000
1983-01-01	13.743800000000000
1984-01-01	16.472900000000000
1985-01-01	18.355999999999998
1986-01-01	19.946400000000000
1987-01-01	21.048800000000000
1988-01-01	16.981600000000000
1989-01-01	18.957900000000000
1990-01-01	20.150300000000000
1991-01-01	19.162300000000000
1992-01-01	19.075100000000000
1993-01-01	19.360400000000000
1994-01-01	17.935800000000000
1995-01-01	17.389200000000000
1996-01-01	18.634800000000000
1997-01-01	21.224300000000000
1998-01-01	21.557900000000000
1999-01-01	19.758300000000000
2000-01-01	18.994900000000000
2001-01-01	19.218500000000000
2002-01-01	17.802100000000000
2003-01-01	15.652999999999999
2004-01-01	16.161700000000000
2005-01-01	18.129800000000000
2006-01-01	22.217700000000000
2007-01-01	26.155700000000000
2008-01-01	28.753300000000000
2009-01-01	31.791800000000000
2010-01-01	29.779600000000000
2011-01-01	30.639500000000000
2012-01-01	33.553400000000000
2013-01-01	33.918200000000000
2014-01-01	30.254100000000000
2015-01-01	30.992200000000000
2016-01-01	31.394200000000000