Year	Percent
1991-01-01	4.39099979400635
1992-01-01	3.86299991607666
1993-01-01	11.41300010681150
1994-01-01	14.24300003051760
1995-01-01	14.47500038146970
1996-01-01	20.05400085449220
1997-01-01	23.22500038146970
1998-01-01	20.14500045776370
1999-01-01	23.90399932861330
2000-01-01	24.49200057983400
2001-01-01	25.47200012207030
2002-01-01	27.70800018310550
2003-01-01	29.38599967956540
2004-01-01	31.63999938964840
2005-01-01	32.19300079345700
2006-01-01	33.73199844360350
2007-01-01	34.61399841308590
2008-01-01	35.79499816894530
2009-01-01	40.71300125122070
2010-01-01	38.96400070190430
2011-01-01	39.05699920654300
2012-01-01	35.28900146484380
2013-01-01	35.75199890136720
2014-01-01	37.05400085449220
2015-01-01	31.96899986267090
2016-01-01	38.59099960327150
2017-01-01	38.58700180053710