Year	Percent
1973-01-01	14.852200000000000
1974-01-01	15.872100000000000
1975-01-01	18.739800000000000
1976-01-01	23.844200000000000
1977-01-01	26.311400000000000
1978-01-01	27.000900000000000
1979-01-01	28.543200000000000
1980-01-01	29.271200000000000
1981-01-01	30.263000000000000
1982-01-01	29.726800000000000
1983-01-01	28.007800000000000
1984-01-01	27.267800000000000
1985-01-01	23.737100000000000
1986-01-01	22.174400000000000
1987-01-01	25.241000000000000
1988-01-01	22.143100000000000
1989-01-01	21.137300000000000
1990-01-01	21.001900000000000
1991-01-01	21.637800000000000
1992-01-01	22.951800000000000
1993-01-01	26.820900000000000
1994-01-01	20.070400000000000
1995-01-01	17.918500000000000
1996-01-01	18.503500000000000
1997-01-01	17.894000000000002
1998-01-01	20.612900000000000
1999-01-01	18.249500000000000
2000-01-01	17.447100000000000
2001-01-01	17.943100000000000
2002-01-01	16.953900000000000
2003-01-01	19.218800000000000
2004-01-01	21.345800000000000
2005-01-01	24.068800000000000
2006-01-01	24.240400000000000
2007-01-01	24.014100000000000
2008-01-01	27.650300000000000
2009-01-01	32.335100000000000
2010-01-01	33.911500000000000
2011-01-01	34.703100000000000
2012-01-01	36.787000000000000
2013-01-01	40.516200000000000
2014-01-01	43.518200000000000
2015-01-01	45.923700000000000
2016-01-01	48.560100000000000