Year Percent 1992-01-01 60.4518000000000000 1993-01-01 32.2170000000000000 1994-01-01 5.8359400000000000 1995-01-01 2.7669500000000000 1996-01-01 2.6337099999999998 1997-01-01 3.2178200000000000 1998-01-01 4.5818900000000005 1999-01-01 6.1806300000000010 2000-01-01 7.6304700000000000 2001-01-01 7.9317000000000000 2002-01-01 7.8759000000000000 2003-01-01 8.0348500000000000 2004-01-01 8.6349600000000010 2005-01-01 9.1135800000000000 2006-01-01 9.3442899999999990 2007-01-01 10.0175000000000000 2008-01-01 10.8212000000000000 2009-01-01 14.5959000000000000 2010-01-01 16.2264000000000000 2011-01-01 18.1103000000000000 2012-01-01 20.0864000000000000 2013-01-01 23.3141000000000000 2014-01-01 25.2784000000000000 2015-01-01 28.0720000000000000 2016-01-01 32.0955000000000000