Year	Percent
1979-01-01	49.0646322248639
1980-01-01	50.2952550667201
1981-01-01	50.9494647560501
1982-01-01	50.8004035432189
1983-01-01	49.7751523788468
1984-01-01	51.4999187924416
1985-01-01	53.5866178556088
1986-01-01	56.5479627657598
1987-01-01	57.6051676152896
1988-01-01	59.5271958211784
1989-01-01	61.8346896644709
1990-01-01	63.1846391322849
1991-01-01	62.3612118548482
1992-01-01	62.1070660956345
1993-01-01	61.7879400311284
1994-01-01	62.7746496984908
1995-01-01	64.7234979826604
1996-01-01	64.5809621602579
1997-01-01	64.8557238716876
1998-01-01	65.2974435435052
1999-01-01	65.6961184384751
2000-01-01	66.9975017644694
2001-01-01	67.4357015818600
2002-01-01	67.9793974545206
2003-01-01	68.9583944138856
2004-01-01	68.7233456851473
2005-01-01	70.6438273054152
2006-01-01	71.2507881371140
2007-01-01	71.8631978336820
2008-01-01	72.4298674822152
2009-01-01	72.0999086315221
2010-01-01	71.8414337039626
2011-01-01	72.3304780854744
2012-01-01	72.2725822117171
2013-01-01	72.2403335531260
2014-01-01	71.9743509810744
2015-01-01	72.5723989370998
2016-01-01	73.0549912082760
2017-01-01	73.9563568199770