Year	Percent
2000-01-01	70.7570234390067
2001-01-01	71.0793348789755
2002-01-01	72.3451923498290
2003-01-01	72.0577496280802
2004-01-01	72.3037838601834
2005-01-01	71.8625336690672
2006-01-01	71.6076863646965
2007-01-01	71.6841786549341
2008-01-01	71.1572890886392
2009-01-01	70.2253104585809
2010-01-01	70.2800579838020
2011-01-01	70.7148404046909
2012-01-01	71.0615216357365
2013-01-01	71.1325844257324
2014-01-01	71.7378362798546
2015-01-01	71.4167610749163
2016-01-01	71.2165566623764
2017-01-01	71.2378874660716