Year	Percent
1991-01-01	11.6105894762740
1992-01-01	11.0832876267355
1993-01-01	11.1511376460546
1994-01-01	11.3544408798042
1995-01-01	11.8540926727785
1996-01-01	12.0599855324579
1997-01-01	12.5324583975791
1998-01-01	13.1973550463333
1999-01-01	13.4366243039787
2000-01-01	13.4607940130432
2001-01-01	13.4150028260932
2002-01-01	13.4831401566845
2003-01-01	13.2617328529415
2004-01-01	13.0256276510201
2005-01-01	12.8919087907484
2006-01-01	12.5588499692947
2007-01-01	12.1193202679868
2008-01-01	12.5293961002365
2009-01-01	12.7491892851516
2010-01-01	12.2402854367933
2011-01-01	12.2631169977908
2012-01-01	12.4126531123822
2013-01-01	12.3568320518492
2014-01-01	12.2727925108219
2015-01-01	12.7300509517886
2016-01-01	13.1608598284380
2017-01-01	13.3010674243859