Year	Percent
1991-01-01	11.0875794801917
1992-01-01	11.4144387368066
1993-01-01	10.8581171279047
1994-01-01	11.2279775236696
1995-01-01	12.3914435223926
1996-01-01	13.3246901340115
1997-01-01	13.2899844003090
1998-01-01	14.8686075687671
1999-01-01	16.1833411248623
2000-01-01	16.2100674255902
2001-01-01	14.9530685023719
2002-01-01	15.7684494865170
2003-01-01	16.1436660866686
2004-01-01	15.7181081044450
2005-01-01	14.6120258081823
2006-01-01	14.4682082285988
2007-01-01	13.6657695758534
2008-01-01	13.4584003749552
2009-01-01	14.9097136979590
2010-01-01	14.0471521816594
2011-01-01	13.6121364676248
2012-01-01	13.4800627213231
2013-01-01	13.3841329082348
2014-01-01	13.2711639997730
2015-01-01	14.3787679665322
2016-01-01	16.9237736556749
2017-01-01	17.7806854008750