Year	Percent
1960-01-01	8.353710000000001
1961-01-01	8.311750000000000
1962-01-01	8.335000000000000
1963-01-01	8.890180000000000
1964-01-01	9.109790000000000
1965-01-01	8.997850000000000
1966-01-01	9.683030000000000
1967-01-01	10.809100000000000
1968-01-01	12.336100000000000
1969-01-01	13.599400000000000
1970-01-01	12.058700000000000
1971-01-01	11.377100000000000
1972-01-01	11.849800000000000
1973-01-01	11.118200000000000
1974-01-01	10.517900000000000
1975-01-01	11.407700000000000
1976-01-01	11.159200000000000
1977-01-01	11.397500000000000
1978-01-01	11.442900000000000
1979-01-01	10.524000000000001
1980-01-01	8.865280000000000
1981-01-01	10.477800000000000
1982-01-01	10.305100000000000
1983-01-01	11.253700000000000
1984-01-01	9.570689999999999
1985-01-01	9.254630000000000
1986-01-01	11.255400000000000
1987-01-01	10.440999999999999
1988-01-01	10.151000000000000
1989-01-01	8.455840000000000
1990-01-01	10.119000000000000
1991-01-01	12.484600000000000
1992-01-01	12.608400000000000
1993-01-01	13.239700000000000
1994-01-01	15.725999999999999
1995-01-01	18.273300000000000
1996-01-01	19.861900000000000
1997-01-01	20.266900000000000
1998-01-01	19.689300000000000
1999-01-01	19.328800000000000
2000-01-01	15.979400000000000
2001-01-01	17.057600000000000
2002-01-01	16.629300000000000
2003-01-01	16.106900000000000
2004-01-01	17.762100000000000
2005-01-01	19.257800000000000
2006-01-01	19.688900000000000
2007-01-01	20.740600000000000
2008-01-01	21.010900000000000
2009-01-01	23.761300000000000
2010-01-01	24.516100000000000
2011-01-01	25.449400000000000
2012-01-01	26.729800000000000
2013-01-01	28.105999999999998
2014-01-01	29.338400000000000
2015-01-01	29.823000000000000
2016-01-01	31.101800000000000