Year	Percent
1960-01-01	11.198400000000000
1961-01-01	9.764520000000000
1962-01-01	8.712570000000000
1963-01-01	9.541980000000000
1964-01-01	9.048760000000001
1965-01-01	8.579239999999999
1966-01-01	9.137060000000000
1967-01-01	10.293700000000000
1968-01-01	11.689900000000000
1969-01-01	13.609100000000000
1970-01-01	14.767600000000000
1971-01-01	15.975999999999999
1972-01-01	16.289500000000000
1973-01-01	16.602500000000000
1974-01-01	14.912500000000000
1975-01-01	13.741600000000000
1976-01-01	13.307900000000000
1977-01-01	13.328100000000000
1978-01-01	12.553900000000000
1979-01-01	14.458800000000000
1980-01-01	16.328500000000000
1981-01-01	18.985700000000000
1982-01-01	25.199800000000000
1983-01-01	28.956500000000000
1984-01-01	28.940700000000000
1985-01-01	28.178300000000000
1986-01-01	29.508500000000000
1987-01-01	18.947400000000000
1988-01-01	22.164100000000000
1989-01-01	12.913500000000000
1990-01-01	13.581900000000000
1991-01-01	8.991750000000000
1992-01-01	10.558800000000000
1993-01-01	11.877600000000000
1994-01-01	10.725900000000000
1995-01-01	13.449000000000002
1996-01-01	19.803900000000000
1997-01-01	25.835200000000000
1998-01-01	30.945300000000000
1999-01-01	30.539200000000000
2000-01-01	31.136300000000000
2001-01-01	31.976200000000000
2002-01-01	32.784000000000000
2003-01-01	30.309900000000000
2004-01-01	26.117600000000000
2005-01-01	25.493300000000000
2006-01-01	25.647200000000000
2007-01-01	25.325000000000000
2008-01-01	26.188900000000000
2009-01-01	27.626900000000000
2010-01-01	27.524700000000000
2011-01-01	28.600400000000000
2012-01-01	30.481400000000000
2013-01-01	33.839600000000000
2014-01-01	36.630300000000000
2015-01-01	37.891900000000000
2016-01-01	36.818700000000000