Add a filter to the following equation

[Sid666123]

Hi,

I've managed to link a custom filter to a single chart using the following equation. However, my goal is to include a filter.

Count({$*[Issue]} ID_number)/Count({1<[Issue]=>} Total ID_number)

How can that be done? 

Cheers,

Sid

[Anil_Babu_Samineni]

Can you explain more?