Creating a Kinana table using a multi-field with es|ql

v 8.17.4
I am trying to create a visualisation table in Kibana using an es|ql query.
The main field in question is a Keyword multi-field call ItemsFound.
I want the first column to be a list of unique items found.
Column two is a count of the ItemsFound
Column three will be a percentage of ItemsFound
I can get the first two columns working just using Kibana but I can't get the percentage, even with a formula.

ItemsFound [ "Item B", "Item W", "Item H" ]
ItemsFound [ "Item B", "Item R", "Item H" ]
ItemsFound [ "Item H", "Item C", "Item F" ]

Items Items count Items %
Item B 60 60%
Item H 30 30%
Item C 15 15%
Item W 5 50