Multiple fields into one bar graph

I am trying to create a bar graph combing multiple fields. I have uploaded a range of 'interests' that people have (some have all, some have none, there is no consistency) as individual checkbox fields, and I would like a graph to show the total values of each interest on one bar graph). I have tried to download them as one field (a 'mutli-select text' field) but that brings up a graph recording each person against all their interests. The final graph does not need to tie interests to individuals, it is just looking for totals.