Year	Percent
1991-01-01	25.5890007019043
1992-01-01	22.4689998626709
1993-01-01	26.3150005340576
1994-01-01	26.1730003356934
1995-01-01	17.8239994049072
1996-01-01	23.5909996032715
1997-01-01	23.5049991607666
1998-01-01	23.2579994201660
1999-01-01	23.3419990539551
2000-01-01	23.5499992370605
2001-01-01	24.2619991302490
2002-01-01	17.4829998016357
2003-01-01	18.0839996337891
2004-01-01	20.5629997253418
2005-01-01	17.2530002593994
2006-01-01	18.7350006103516
2007-01-01	16.1429996490479
2008-01-01	18.4300003051758
2009-01-01	13.9130001068115
2010-01-01	16.4729995727539
2011-01-01	17.2660007476807
2012-01-01	16.6189994812012
2013-01-01	17.4890003204346
2014-01-01	17.8710002899170
2015-01-01	18.0869998931885
2016-01-01	17.8819999694824
2017-01-01	17.7439994812012