Year	Percent
1960-01-01	15.100999999999999
1961-01-01	16.864400000000000
1962-01-01	19.627000000000000
1963-01-01	20.391400000000000
1964-01-01	22.896500000000000
1965-01-01	22.920600000000000
1966-01-01	23.146300000000000
1967-01-01	23.994800000000000
1968-01-01	25.042200000000000
1969-01-01	25.277200000000000
1970-01-01	22.444600000000000
1971-01-01	22.548300000000000
1972-01-01	23.562500000000000
1973-01-01	23.727100000000000
1974-01-01	23.144800000000000
1975-01-01	24.134900000000000
1976-01-01	26.489100000000000
1977-01-01	28.070400000000000
1978-01-01	29.709600000000000
1979-01-01	31.075500000000000
1980-01-01	34.594400000000000
1981-01-01	37.184100000000000
1982-01-01	39.813400000000000
1983-01-01	39.162400000000000
1984-01-01	34.347500000000000
1985-01-01	27.111900000000000
1986-01-01	19.180800000000000
1987-01-01	15.333700000000000
1988-01-01	16.013800000000000
1989-01-01	16.562100000000000
1990-01-01	17.524600000000000
1991-01-01	18.772400000000000
1992-01-01	20.337000000000000
1993-01-01	24.718000000000004
1994-01-01	29.415900000000000
1995-01-01	34.994300000000000
1996-01-01	42.963200000000000
1997-01-01	50.288000000000004
1998-01-01	50.549100000000000
1999-01-01	43.711000000000006
2000-01-01	39.849600000000000
2001-01-01	37.784000000000000
2002-01-01	34.889600000000000
2003-01-01	32.721700000000000
2004-01-01	30.861700000000000
2005-01-01	29.165500000000000
2006-01-01	27.760800000000000
2007-01-01	26.951300000000000
2008-01-01	27.450900000000000
2009-01-01	28.650000000000000
2010-01-01	27.787800000000000
2011-01-01	29.873300000000000
2012-01-01	31.479700000000000
2013-01-01	33.122700000000000
2014-01-01	36.140300000000000
2015-01-01	39.422300000000000
2016-01-01	41.409700000000000