Would the rates and frequencies reported in the Categorical platform help you.

I've attached an example of the Categorical report when you have multiple open boxes for one question. In this case, the question was "When do you floss (check all that apply)?" The numbers in the Cross tab are as follows.

Freq is the number of people who checked the box.

Share is the number of people who checked the box divided by the total number of boxes that were checked.

Rate is the number of people who checked the box divided by the number of people in the survey.

Rate per Case Responding is the number of people who checked the box divided by the number of people who checked at least one box.

Check out the "Indicator Group" section of this part of the JMP documentation to see how to create the report you need:

http://www.jmp.com/support/help/Additional_Examples_of_the_Categorical_Platform.shtml