Year	Percent
1991-01-01	45.7840003967285
1992-01-01	45.7169990539551
1993-01-01	45.6930007934570
1994-01-01	45.6660003662109
1995-01-01	45.5999984741211
1996-01-01	45.4319992065430
1997-01-01	45.2529983520508
1998-01-01	45.0779991149902
1999-01-01	44.9000015258789
2000-01-01	44.7500000000000
2001-01-01	44.5190010070801
2002-01-01	44.3429985046387
2003-01-01	44.1969985961914
2004-01-01	44.0620002746582
2005-01-01	43.9269981384277
2006-01-01	43.7550010681152
2007-01-01	43.5929985046387
2008-01-01	43.4440002441406
2009-01-01	43.3279991149902
2010-01-01	43.2680015563965
2011-01-01	43.1660003662109
2012-01-01	43.1230010986328
2013-01-01	43.1290016174316
2014-01-01	43.1699981689453
2015-01-01	43.2350006103516
2016-01-01	43.3079986572266
2017-01-01	43.3520011901855