How to put variables on individual items of the same type in the lore/special information section

I am making a mod where when you right click on a villager with a empty contract it gets changed into a dfilled contract with randomly assigned values. I cant get the item to say the values. I tried using <ENBT:number:mining> in the special information section but it just said "<ENBT:number:mining>". I want it to be like the chickens for the roost mod, here is a picture of that:

Here is my block code for getting the new item:

I apologize if I don't reply often, I might not be paying attention. Please help me