Year	Percent
1991-01-01	47.5693
1992-01-01	50.0714
1993-01-01	48.4646
1994-01-01	43.7099
1995-01-01	47.5169
1996-01-01	47.4391
1997-01-01	44.7469
1998-01-01	44.8269
1999-01-01	48.3181
2000-01-01	47.3311
2001-01-01	47.9613
2002-01-01	51.5638
2003-01-01	55.2201
2004-01-01	53.2129
2005-01-01	53.0501
2006-01-01	53.3978
2007-01-01	50.2959
2008-01-01	54.7239
2009-01-01	65.0876
2010-01-01	67.3245
2011-01-01	65.2206
2012-01-01	68.9431
2013-01-01	68.1921
2014-01-01	66.0397
2015-01-01	70.0680