Calculations across records
I'm new to Filemaker Pro and am having trouble with some particular calculations.
I have created a medical database to collect information regarding patients operations.
I need to calculate the percentage of records that return a specific value for a particular field.
For example, the Margin Status field has a drop down with the values "Positive", Negative" and "Abuts" which relates to the margin status of a resected tumour (ie tumour is positive at the resected margin, negative, or abuts against the resected margin). I would like to calculate the percentage of patients with a "Positive Margin" within the whole database. I have tried a subsummary count of patients with "Positive" in the Margin status field, but don't know how to divide this by the number of patients in the database. I would like to have to percentage updated each time a new patient is added to the database, and viewed within the main layout of the database.
Filemaker Pro 11