How to use the internal id of the Tax Code assigned to a Customer record on a Customer Search

1. Navigate to Lists > Search > Saved Searches > New. 
2. Select Customer
3. In the Criteria tab > Standard subtab, set the following:
-- Filter = Formula (Text)
-- Description = is -7 (Not Taxable)
-- Formula =  {taxitem.id}
4.In the Results tab > Columns subtab, set the following:
--ID
--Name
--Tax Item
--Formula (Text) then under the formula column enter {taxitem.id}
5. Rename search and click on Save & Run