Year	Percent
1991-01-01	24.8430004119873
1992-01-01	23.7679996490479
1993-01-01	24.5380001068115
1994-01-01	29.9279994964600
1995-01-01	28.5860004425049
1996-01-01	28.2420005798340
1997-01-01	29.6970005035400
1998-01-01	29.6049995422363
1999-01-01	29.5270004272461
2000-01-01	27.3419990539551
2001-01-01	27.8710002899170
2002-01-01	30.1930007934570
2003-01-01	33.3829994201660
2004-01-01	40.8919982910156
2005-01-01	46.3440017700195
2006-01-01	47.3689994812012
2007-01-01	42.9770011901855
2008-01-01	34.4519996643066
2009-01-01	39.5940017700195
2010-01-01	45.5970001220703
2011-01-01	50.5309982299805
2012-01-01	50.6049995422363
2013-01-01	48.7910003662109
2014-01-01	46.7089996337891
2015-01-01	42.5900001525879
2016-01-01	34.4339981079102
2017-01-01	32.8219985961914