Year % of total 1990 2.5365470185392 1995 0.929522190398335 2000 0.796000879472158 2005 0.050626694387923 2010 0.00341583459493315 2011 0.00493617975558805 2012 0.02959952902577 2013 0.091259003691102 2014 0.00642573744795709 2015 0.0421709078359255 2016 0.00334082970782081 2017 0.00528204094669695