Year	Percent
1991-01-01	45.4799995422363
1992-01-01	44.2220001220703
1993-01-01	43.3520011901855
1994-01-01	42.4490013122559
1995-01-01	41.8100013732910
1996-01-01	41.8019981384277
1997-01-01	41.7099990844727
1998-01-01	41.8419990539551
1999-01-01	42.2420005798340
2000-01-01	42.6469993591309
2001-01-01	43.3940010070801
2002-01-01	43.9710006713867
2003-01-01	44.5000000000000
2004-01-01	45.6800003051758
2005-01-01	45.2130012512207
2006-01-01	45.6160011291504
2007-01-01	45.6819992065430
2008-01-01	45.6440010070801
2009-01-01	44.5279998779297
2010-01-01	43.9589996337891
2011-01-01	43.8520011901855
2012-01-01	43.5299987792969
2013-01-01	42.4459991455078
2014-01-01	42.3549995422363
2015-01-01	42.6110000610352
2016-01-01	43.1360015869141
2017-01-01	43.1669998168945