Percentages in pivot table

[#1]

Hi,

A simple question.

The pivot table has two dimensions. How do I get fractions of the new concepts to total concepts in a period ? and also old concepts to total concepts and sums of concepts in each period.

[#2]

How to get the concepts that are not unique in jan & not unique in april & not unique in Jul & not unique in Oct ??

[#3]

HOw do I identify concepts that have died out over time ?

and the concepts that have sustained over the entire time frame ?