Year	Percent
1991-01-01	43.5419
1992-01-01	43.8269
1993-01-01	41.5718
1994-01-01	39.0081
1995-01-01	43.7966
1996-01-01	45.3207
1997-01-01	44.3445
1998-01-01	42.7606
1999-01-01	44.2999
2000-01-01	44.5344
2001-01-01	46.3995
2002-01-01	50.2270
2003-01-01	54.7337
2004-01-01	53.7692
2005-01-01	55.1864
2006-01-01	57.1984
2007-01-01	54.5538
2008-01-01	55.4612
2009-01-01	60.0438
2010-01-01	62.1035
2011-01-01	63.0388
2012-01-01	66.7055
2013-01-01	67.9101
2014-01-01	68.2131
2015-01-01	68.5241