Year	Percent
1991-01-01	11.6714418285955
1992-01-01	12.0265033288909
1993-01-01	12.0423892280890
1994-01-01	12.6797904058978
1995-01-01	14.7273420878854
1996-01-01	15.4479335665337
1997-01-01	15.0318679993628
1998-01-01	16.0755040311399
1999-01-01	17.5869786536773
2000-01-01	17.7705466243312
2001-01-01	17.0424350654736
2002-01-01	18.1557967446593
2003-01-01	17.8278707556472
2004-01-01	16.9006230550567
2005-01-01	15.6551680640472
2006-01-01	15.2981908268792
2007-01-01	14.3269920838668
2008-01-01	14.0557873417036
2009-01-01	15.6210424852178
2010-01-01	14.6660695318947
2011-01-01	14.1708197915472
2012-01-01	13.9731596312702
2013-01-01	13.9540614060625
2014-01-01	13.8259201043303
2015-01-01	14.8636350768671
2016-01-01	17.3527065229908
2017-01-01	18.1426121870277