Year Percent 1990 1.37974 1991 1.34654 1992 1.52373 1993 1.55368 1994 1.56503 1995 2.19935 1996 2.17136 1997 1.97331 1998 1.98475 1999 1.96431 2000 1.96795 2001 1.52453 2002 1.5176 2003 1.37178 2004 0.59711 2005 0.60978 2006 0.51584 2007 0.36327 2008 0.35885 2009 0.4452 2010 0.4285 2011 0.42631 2012 0.3202 2013 0.31639 2014 0.59527 2015 0.59009 2016 0.58257 2017 0.56273 2018 0.28074 2019 0.2749 2020 0.27461