Year	Percent
1964-01-01	2.6479200000000000
1965-01-01	2.3357600000000000
1966-01-01	2.5011900000000002
1967-01-01	2.5614000000000000
1968-01-01	2.6619000000000000
1969-01-01	2.6545900000000002
1970-01-01	3.8280700000000000
1971-01-01	4.5164500000000000
1972-01-01	4.6994000000000000
1973-01-01	4.8371500000000000
1974-01-01	4.9580100000000000
1975-01-01	4.5935300000000000
1976-01-01	5.2860700000000000
1977-01-01	6.1209700000000000
1978-01-01	6.6249400000000000
1979-01-01	6.6991900000000000
1980-01-01	6.5946700000000000
1981-01-01	6.2435199999999990
1982-01-01	6.2544699999999995
1983-01-01	6.2064300000000000
1984-01-01	6.5100100000000000
1985-01-01	7.0744100000000000
1986-01-01	8.4483400000000000
1987-01-01	9.6627600000000000
1988-01-01	10.4608000000000000
1989-01-01	10.0372000000000000
1990-01-01	9.9139300000000000
1991-01-01	9.8887500000000000
1992-01-01	9.3623200000000000
1993-01-01	9.6504400000000000
1994-01-01	9.6504400000000000
1995-01-01	13.2711000000000000
1996-01-01	11.1495000000000000
1997-01-01	10.2623000000000000
1998-01-01	11.1234000000000000
1999-01-01	11.7590000000000000
2000-01-01	12.0593000000000000
2001-01-01	12.7348000000000000
2002-01-01	13.4790000000000010
2003-01-01	12.5700000000000000
2004-01-01	13.0606000000000000
2005-01-01	13.5398000000000000
2006-01-01	12.8658000000000000
2007-01-01	13.3163000000000000
2008-01-01	13.1412000000000000
2009-01-01	12.2025000000000000
2010-01-01	12.3674000000000000
2011-01-01	13.9979000000000000
2012-01-01	15.2817000000000000
2013-01-01	15.7041000000000000
2014-01-01	16.4623000000000000
2015-01-01	17.7406000000000000
2016-01-01	17.8295000000000000