In percent, how many more people in a September 2014 poll supported same-sex marriage than had or stated no opinion?
return the  September 2014 poll ;return people that supported same-sex marriage of #1 ;return people that had or  stated no opinion of same-sex marriage of  #1 ;return percent of #2 ;return percent of #3 ;return the  difference of #4 and  #5
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