Year	Percent
1991-01-01	23.6714305440173
1992-01-01	23.7445696445457
1993-01-01	25.1404013917052
1994-01-01	26.0821219378917
1995-01-01	26.6826504720745
1996-01-01	26.2218781370370
1997-01-01	26.4014868248044
1998-01-01	26.2647660740272
1999-01-01	23.5669936299447
2000-01-01	23.0281159905394
2001-01-01	25.0061989359547
2002-01-01	25.2042103144009
2003-01-01	25.5763657161190
2004-01-01	26.3507156687526
2005-01-01	25.6626243698840
2006-01-01	23.8860299134865
2007-01-01	24.2595493367904
2008-01-01	23.9704217019680
2009-01-01	24.9826069353174
2010-01-01	24.4941935616588
2011-01-01	23.9297967382232
2012-01-01	22.7087545119983
2013-01-01	23.6980257134257
2014-01-01	23.2600808840034
2015-01-01	23.6426794771986
2016-01-01	23.9444974832923
2017-01-01	23.7536355135873