Year Percent 1996 24.65791 1997 10.16998 1998 7.89323 1999 7.44564 2000 3.76053 2001 6.32597 2002 5.04795 2003 4.29339 2004 4.86741 2005 6.0717 2006 8.87791 2007 11.51046 2008 7.49281 2009 0.43069 2010 1.73588 2011 5.2609 2012 3.15975 2013 3.55574 2014 1.47205 2015 1.24619 2016 1.59269 2017 3.97728