Year	Percent
1979-01-01	44.8754794021500
1980-01-01	44.8787691096069
1981-01-01	43.8958955916418
1982-01-01	42.3931308873318
1983-01-01	41.5375572151054
1984-01-01	41.2386118153838
1985-01-01	40.6650459177142
1986-01-01	41.6369994491461
1987-01-01	41.8034701442997
1988-01-01	42.2606983092182
1989-01-01	43.1775986741783
1990-01-01	43.9005038341174
1991-01-01	43.6159853371775
1992-01-01	43.4732916401462
1993-01-01	43.3375387018206
1994-01-01	44.6091097661789
1995-01-01	45.0432871377006
1996-01-01	45.7541321688763
1997-01-01	45.8166955945671
1998-01-01	46.5487884641667
1999-01-01	46.5845629686026
2000-01-01	48.2379051000362
2001-01-01	48.9592074015961
2002-01-01	50.6426677332434
2003-01-01	52.2530651257638
2004-01-01	53.6000970710832
2005-01-01	55.3354020502006
2006-01-01	57.2633952200160
2007-01-01	58.0966517802224
2008-01-01	58.8472473345884
2009-01-01	61.0550042813987
2010-01-01	62.6401545878881
2011-01-01	63.2630410545374
2012-01-01	63.6271753568554
2013-01-01	63.8412801806512
2014-01-01	64.0363457644612
2015-01-01	64.8718326585656
2016-01-01	65.2413597148287
2017-01-01	66.2815371581686