Year	Percent
1960-01-01	11.028600000000000
1961-01-01	11.513000000000000
1962-01-01	12.298100000000000
1963-01-01	15.177200000000000
1964-01-01	17.147700000000000
1965-01-01	15.440900000000000
1966-01-01	15.468800000000000
1967-01-01	19.175900000000000
1968-01-01	17.740200000000000
1969-01-01	18.746200000000000
1970-01-01	15.995100000000000
1971-01-01	17.047700000000000
1972-01-01	15.306500000000000
1973-01-01	16.360800000000000
1974-01-01	16.296900000000000
1975-01-01	16.253200000000000
1976-01-01	15.501100000000000
1977-01-01	17.843400000000000
1978-01-01	21.306700000000000
1979-01-01	21.904700000000000
1980-01-01	22.456500000000000
1981-01-01	25.968800000000000
1982-01-01	34.584600000000000
1983-01-01	32.079800000000000
1984-01-01	30.753300000000000
1985-01-01	37.177600000000000
1986-01-01	37.453800000000000
1987-01-01	26.530300000000000
1988-01-01	31.197100000000000
1989-01-01	24.052300000000000
1990-01-01	25.669500000000000
1991-01-01	27.164400000000000
1992-01-01	31.100800000000000
1993-01-01	21.405800000000000
1994-01-01	18.693200000000000
1995-01-01	11.907600000000000
1996-01-01	9.170370000000000
1997-01-01	7.392570000000000
1998-01-01	7.944520000000000
1999-01-01	8.712740000000000
2000-01-01	9.609639999999999
2001-01-01	11.467200000000000
2002-01-01	12.870000000000000
2003-01-01	14.124100000000000
2004-01-01	15.451300000000000
2005-01-01	18.608500000000000
2006-01-01	20.238900000000000
2007-01-01	20.174300000000000
2008-01-01	19.547300000000000
2009-01-01	21.322500000000000
2010-01-01	21.288400000000000
2011-01-01	22.072600000000000
2012-01-01	23.406400000000000
2013-01-01	20.237400000000000
2014-01-01	18.129500000000000
2015-01-01	17.588300000000000