Year	Percent
1991-01-01	25.6870002746582
1992-01-01	27.6970005035400
1993-01-01	31.1070003509521
1994-01-01	37.8670005798340
1995-01-01	38.4440002441406
1996-01-01	36.9959983825684
1997-01-01	34.2169990539551
1998-01-01	30.4060001373291
1999-01-01	27.2870006561279
2000-01-01	24.1900005340576
2001-01-01	39.4490013122559
2002-01-01	38.7229995727539
2003-01-01	43.4780006408691
2004-01-01	40.7270011901855
2005-01-01	38.0219993591309
2006-01-01	32.0340003967285
2007-01-01	32.2509994506836
2008-01-01	32.4990005493164
2009-01-01	32.5019989013672
2010-01-01	35.2369995117188
2011-01-01	35.1710014343262
2012-01-01	35.1590003967285
2013-01-01	35.5050010681152
2014-01-01	35.2309989929199
2015-01-01	34.9970016479492
2016-01-01	35.2729988098145
2017-01-01	35.6959991455078