Year	Percent
1978-01-01	80.3121190306380
1979-01-01	80.3843973710056
1980-01-01	80.1865107007218
1981-01-01	80.0220081948305
1982-01-01	79.7163480282847
1983-01-01	79.5324453579771
1984-01-01	78.9667052081832
1985-01-01	78.4519315887441
1986-01-01	78.0054958630335
1987-01-01	77.6207054064752
1988-01-01	77.7615974843532
1989-01-01	77.9163894707645
1990-01-01	78.3224898598716
1991-01-01	78.8312736087194
1992-01-01	79.1984156824519
1993-01-01	79.0758427823783
1994-01-01	78.5635225828014
1995-01-01	78.2553595128416
1996-01-01	78.2393271292120
1997-01-01	78.3222289351087
1998-01-01	77.3201908484564
1999-01-01	76.5645167880942
2000-01-01	76.2077955257037
2001-01-01	75.4875666548942
2002-01-01	74.6402940254950
2003-01-01	74.3377381250381
2004-01-01	74.3364095961727
2005-01-01	74.7033420622879
2006-01-01	75.1129017114271
2007-01-01	75.6775173865131
2008-01-01	75.4981228545409
2009-01-01	74.0649995171189
2010-01-01	73.8339641573938
2011-01-01	74.0954556983852
2012-01-01	74.0685507875475
2013-01-01	74.3877726836453
2014-01-01	74.8916727494956
2015-01-01	75.2099591670653
2016-01-01	75.8385708428081
2017-01-01	76.3789596724671