Year	Percent
1965-01-01	19.611900000000000
1966-01-01	19.557600000000000
1967-01-01	19.796500000000000
1968-01-01	19.802100000000000
1969-01-01	20.169100000000000
1970-01-01	20.522200000000000
1971-01-01	21.250500000000000
1972-01-01	23.094000000000000
1973-01-01	24.332600000000000
1974-01-01	25.316600000000000
1975-01-01	26.845500000000000
1976-01-01	26.761999999999997
1977-01-01	26.057900000000000
1978-01-01	27.391600000000000
1979-01-01	27.435600000000000
1980-01-01	28.640900000000000
1981-01-01	31.922300000000000
1982-01-01	34.843600000000000
1983-01-01	36.409200000000000
1984-01-01	39.230300000000000
1985-01-01	47.039500000000000
1986-01-01	45.700900000000000
1987-01-01	33.125800000000000
1988-01-01	34.285700000000000
1989-01-01	36.090000000000000
1990-01-01	32.985700000000000
1991-01-01	29.030800000000000
1992-01-01	29.385700000000000
1993-01-01	32.127900000000000
1994-01-01	37.941600000000000
1995-01-01	40.129100000000000
1996-01-01	41.900900000000000
1997-01-01	43.508700000000000
1998-01-01	44.034100000000000
1999-01-01	45.755800000000000
2000-01-01	45.901300000000000
2001-01-01	45.507400000000000
2002-01-01	44.962200000000000
2003-01-01	42.818800000000000
2004-01-01	41.871600000000000
2005-01-01	39.887900000000000
2006-01-01	39.028400000000000
2007-01-01	40.863000000000000
2008-01-01	42.284500000000000
2009-01-01	43.282100000000000
2010-01-01	43.065700000000000
2011-01-01	41.261300000000000
2012-01-01	39.991600000000000
2013-01-01	40.175000000000000
2014-01-01	39.672500000000000
2015-01-01	38.761700000000000
2016-01-01	39.788500000000000