Year	Percent
1960-01-01	8.514090000000000
1961-01-01	8.636540000000000
1962-01-01	9.236540000000000
1963-01-01	9.084470000000000
1964-01-01	8.902740000000000
1965-01-01	9.294880000000001
1966-01-01	9.578820000000000
1967-01-01	9.499939999999999
1968-01-01	10.198800000000000
1969-01-01	10.607999999999999
1970-01-01	10.391200000000000
1971-01-01	11.366800000000000
1972-01-01	12.152400000000000
1973-01-01	11.786700000000000
1974-01-01	11.733500000000000
1975-01-01	12.649200000000000
1976-01-01	15.554000000000000
1977-01-01	17.575400000000000
1978-01-01	18.330300000000000
1979-01-01	19.605800000000000
1980-01-01	18.647700000000000
1981-01-01	19.268200000000000
1982-01-01	20.297800000000000
1983-01-01	20.942400000000000
1984-01-01	22.033500000000000
1985-01-01	22.584000000000000
1986-01-01	23.501900000000000
1987-01-01	23.590000000000000
1988-01-01	22.942700000000000
1989-01-01	23.497700000000000
1990-01-01	23.365500000000000
1991-01-01	22.384600000000000
1992-01-01	22.571900000000000
1993-01-01	22.129400000000000
1994-01-01	21.683700000000000
1995-01-01	21.187400000000000
1996-01-01	21.036700000000000
1997-01-01	21.740900000000000
1998-01-01	21.975800000000000
1999-01-01	22.539600000000000
2000-01-01	25.646000000000000
2001-01-01	26.906200000000000
2002-01-01	28.950600000000000
2003-01-01	29.846000000000000
2004-01-01	31.500800000000000
2005-01-01	35.261400000000000
2006-01-01	38.441600000000000
2007-01-01	41.025400000000000
2008-01-01	44.374900000000000
2009-01-01	44.521000000000000
2010-01-01	44.059700000000000
2011-01-01	47.794400000000000
2012-01-01	48.739700000000000
2013-01-01	49.536300000000000
2014-01-01	49.795100000000000
2015-01-01	49.858300000000000
2016-01-01	48.758500000000000