Year	Percent
1961-01-01	29.443500000000000
1962-01-01	28.149600000000000
1963-01-01	26.689700000000000
1964-01-01	30.161800000000000
1965-01-01	29.940300000000000
1966-01-01	28.829400000000000
1967-01-01	28.017100000000000
1968-01-01	32.327200000000000
1969-01-01	31.882700000000000
1970-01-01	22.802500000000000
1971-01-01	22.833600000000000
1972-01-01	24.376200000000000
1973-01-01	23.316100000000000
1974-01-01	25.599100000000000
1975-01-01	29.548400000000000
1976-01-01	29.836800000000000
1977-01-01	31.333200000000000
1978-01-01	33.103400000000000
1979-01-01	31.085100000000000
1980-01-01	31.806800000000000
1981-01-01	31.897300000000000
1982-01-01	31.965900000000000
1983-01-01	34.661400000000000
1984-01-01	34.838400000000000
1985-01-01	36.125900000000000
1986-01-01	35.197900000000000
1987-01-01	38.517600000000000
1988-01-01	40.557500000000000
1989-01-01	41.464800000000000
1990-01-01	44.471000000000004
1991-01-01	51.703000000000000
1992-01-01	52.483300000000000
1993-01-01	53.221700000000000
1994-01-01	51.642500000000000
1995-01-01	51.805300000000000
1996-01-01	49.686700000000000
1997-01-01	47.528100000000000
1998-01-01	41.638200000000000
1999-01-01	37.365000000000000
2000-01-01	41.894600000000000
2001-01-01	37.329400000000000
2002-01-01	32.549900000000000
2003-01-01	33.724200000000000
2004-01-01	37.168300000000000
2005-01-01	40.621700000000000
2006-01-01	44.843000000000000
2007-01-01	48.184800000000000
2008-01-01	46.459500000000000
2009-01-01	47.130200000000000
2010-01-01	46.279600000000000
2011-01-01	46.165100000000000
2012-01-01	46.364300000000000
2013-01-01	46.690000000000000
2014-01-01	47.457900000000000
2015-01-01	50.350000000000000
2016-01-01	53.565300000000000