Year	Percent
1995-01-01	15
1996-01-01	16
1997-01-01	16
1998-01-01	15
1999-01-01	17
2000-01-01	19
2001-01-01	21
2002-01-01	21
2003-01-01	21
2004-01-01	23
2005-01-01	24
2006-01-01	24
2007-01-01	26
2008-01-01	28
2009-01-01	31
2010-01-01	32
2011-01-01	33
2012-01-01	31
2013-01-01	31