Year % of total 1990 0 1991 0 1992 0 1993 0 1994 0 1995 0 1996 0 1997 0 1998 0 1999 0.23375056552556178 2000 0.5137991779213152 2001 0.4977187888842804 2002 0.6987258528565558 2003 0.8827785817655571 2004 0.7923515159452558 2005 0.7541178805318516 2006 0.740985775719484 2007 0.7511799508076846 2008 1.7684005122263553 2009 1.1705175882460526 2010 1.4211011996308829 2011 1.9981149858623939 2012 2.7656290198096216 2013 3.0425706875830225 2014 3.023946862436637 2015 3.691705473442667