Jane,
if the Ash % is not on the bag, email the company, or call them. They are usually more than happy to give you that information. I have emailed pet food companies in regards to calories per cup on my cat's food and also to find out what "Natural flavor" meant on their ingredient list because my cat has allergies. I got responses very quickly.
Here is the link to Innova - the Contact info is on the side. Hope this helps.
http://www.naturapet.com/display.php?d=home-tab