Year	Percent
1973-01-01	16.673900000000000
1974-01-01	17.424500000000000
1975-01-01	18.546800000000000
1976-01-01	17.957900000000000
1977-01-01	17.290900000000000
1978-01-01	20.345300000000000
1979-01-01	29.737200000000000
1980-01-01	37.875800000000000
1981-01-01	41.870200000000000
1982-01-01	39.995600000000000
1983-01-01	40.671800000000000
1984-01-01	34.591700000000000
1985-01-01	21.823900000000000
1986-01-01	15.877900000000000
1987-01-01	15.408700000000000
1988-01-01	22.863700000000000
1989-01-01	10.494000000000002
1990-01-01	15.655800000000000
1991-01-01	6.390150000000000
1992-01-01	10.024700000000000
1993-01-01	10.970700000000000
1994-01-01	13.849800000000000
1995-01-01	14.900200000000000
1996-01-01	14.332300000000000
1997-01-01	14.875800000000000
1998-01-01	20.559300000000000
1999-01-01	21.308200000000000
2000-01-01	24.453500000000000
2001-01-01	20.196300000000000
2002-01-01	17.014300000000000
2003-01-01	19.672000000000000
2004-01-01	22.462600000000000
2005-01-01	25.296000000000000
2006-01-01	28.271700000000000
2007-01-01	30.367800000000000
2008-01-01	30.800500000000000
2009-01-01	29.213900000000000
2010-01-01	26.815600000000000
2011-01-01	25.723200000000000
2012-01-01	26.965000000000000
2013-01-01	30.073100000000000
2014-01-01	31.520300000000000
2015-01-01	33.362200000000000
2016-01-01	36.884800000000000