Year	Percent
1975-01-01	47.19350000000000
1976-01-01	43.94580000000000
1977-01-01	44.11000000000000
1978-01-01	42.15220000000000
1979-01-01	45.68680000000000
1980-01-01	44.55370000000000
1981-01-01	39.76260000000000
1982-01-01	41.46020000000000
1983-01-01	43.62720000000000
1984-01-01	41.44550000000000
1985-01-01	44.14700000000000
1986-01-01	48.82180000000000
1987-01-01	50.18290000000000
1988-01-01	50.51390000000000
1989-01-01	56.80270000000000
1990-01-01	57.49650000000000
1991-01-01	56.93230000000000
1992-01-01	55.48330000000000
1993-01-01	58.72910000000000
1994-01-01	61.96020000000000
1995-01-01	60.40250000000000
1996-01-01	61.82720000000000
1997-01-01	63.43730000000000
1998-01-01	66.52860000000000
1999-01-01	72.21670000000000
2000-01-01	77.55590000000000
2001-01-01	75.37899999999999
2002-01-01	74.23340000000000
2003-01-01	72.07170000000000
2004-01-01	69.52530000000000
2005-01-01	69.37260000000000
2006-01-01	64.46920000000000
2007-01-01	64.49330000000000
2008-01-01	65.00110000000000
2009-01-01	65.65470000000000
2010-01-01	66.22990000000000
2011-01-01	68.36950000000000
2012-01-01	68.88170000000000
2013-01-01	70.25540000000000
2014-01-01	75.18640000000000
2015-01-01	76.42920000000000
2016-01-01	77.52050000000000