Year	Percent
1960-01-01	15.651900000000000
1961-01-01	15.734000000000002
1962-01-01	16.003200000000000
1963-01-01	16.210500000000000
1964-01-01	16.032600000000000
1965-01-01	16.079800000000000
1966-01-01	16.560900000000000
1967-01-01	17.311100000000000
1968-01-01	19.083900000000000
1969-01-01	20.810400000000000
1970-01-01	18.796100000000000
1971-01-01	17.762400000000000
1972-01-01	18.405000000000000
1973-01-01	17.687600000000000
1974-01-01	17.023100000000000
1975-01-01	18.239000000000000
1976-01-01	17.804800000000000
1977-01-01	18.601900000000000
1978-01-01	18.436400000000000
1979-01-01	17.409200000000000
1980-01-01	15.374700000000000
1981-01-01	18.194700000000000
1982-01-01	18.128000000000000
1983-01-01	20.162800000000000
1984-01-01	16.896700000000000
1985-01-01	15.314400000000000
1986-01-01	17.116900000000000
1987-01-01	15.710900000000000
1988-01-01	15.561600000000000
1989-01-01	13.333700000000000
1990-01-01	14.646400000000000
1991-01-01	16.655300000000000
1992-01-01	16.171200000000000
1993-01-01	16.792700000000000
1994-01-01	19.762999999999998
1995-01-01	21.993700000000000
1996-01-01	23.044500000000000
1997-01-01	23.225200000000000
1998-01-01	22.383100000000000
1999-01-01	22.817400000000000
2000-01-01	19.995300000000000
2001-01-01	18.609900000000000
2002-01-01	17.745500000000000
2003-01-01	17.015700000000000
2004-01-01	18.700700000000000
2005-01-01	20.373200000000000
2006-01-01	21.002100000000000
2007-01-01	22.267700000000000
2008-01-01	22.736500000000000
2009-01-01	25.582300000000000
2010-01-01	26.046900000000000
2011-01-01	26.896300000000000
2012-01-01	28.300200000000000
2013-01-01	29.835800000000000
2014-01-01	31.328400000000000
2015-01-01	31.761400000000000
2016-01-01	33.030500000000000