Year	Percent
1991-01-01	34.4459991455078
1992-01-01	33.6689987182617
1993-01-01	33.0800018310547
1994-01-01	32.5740013122559
1995-01-01	30.6870002746582
1996-01-01	32.0800018310547
1997-01-01	33.2330017089844
1998-01-01	32.4070014953613
1999-01-01	31.4580001831055
2000-01-01	30.6009998321533
2001-01-01	31.4860000610352
2002-01-01	31.9200000762939
2003-01-01	32.7029991149902
2004-01-01	35.1580009460449
2005-01-01	36.0429992675781
2006-01-01	37.2029991149902
2007-01-01	36.4580001831055
2008-01-01	37.4119987487793
2009-01-01	37.8429985046387
2010-01-01	38.1430015563965
2011-01-01	38.2729988098145
2012-01-01	38.0000000000000
2013-01-01	39.3940010070801
2014-01-01	37.1160011291504
2015-01-01	36.8310012817383
2016-01-01	37.1839981079102
2017-01-01	37.2369995117188