Year	Percent
1991-01-01	64.0070037841797
1992-01-01	64.5149993896484
1993-01-01	65.3059997558594
1994-01-01	66.4290008544922
1995-01-01	66.6529998779297
1996-01-01	67.2360000610352
1997-01-01	66.9010009765625
1998-01-01	66.6940002441406
1999-01-01	66.6600036621094
2000-01-01	66.7180023193359
2001-01-01	66.5059967041016
2002-01-01	66.4420013427734
2003-01-01	66.7460021972656
2004-01-01	66.8570022583008
2005-01-01	67.1809997558594
2006-01-01	67.4670028686523
2007-01-01	67.3899993896484
2008-01-01	67.5240020751953
2009-01-01	68.2580032348633
2010-01-01	68.7399978637695
2011-01-01	67.6959991455078
2012-01-01	67.9010009765625
2013-01-01	68.0930023193359
2014-01-01	68.5049972534180
2015-01-01	68.9140014648438
2016-01-01	68.0530014038086
2017-01-01	67.5520019531250