Formats

OK I am a little stumped.  I have created a formula field that is based, in part on dates (two dates are subtracted from each other in the formula).  The formula calculates to a percentage, and it correctly displays as a percentage on the form.  When I add this field to the table view, however, it displays as a date rather than a percentage.  Why would the field display differently on the form vs the tabel view?

Here is the formula: ('Discount/Premium' / 'Years to Call' + 'Div / Share') / (('Current Price' + 'Call Price') / 2) * 100

The field "Years to Call" is calculated as the difference between a future date and today.