Year Percent 1994 2.711 1995 2.8941 1996 3.4723 1997 3.2845 1998 5.7344 1999 3.4337 2000 5.8644 2001 5.1582 2002 3.8316 2003 3.8569 2004 4.7144 2005 2.9797 2006 2.5097 2007 3.5267 2008 2.7501 2009 2.5011 2010 1.9178 2011 2.4827 2012 2.7215 2013 3.2169 2014 2.8428 2015 3.3943 2016 3.7598 2017 3.7041