It's really not an answerable question unfortunately. Codeine, like all drugs, is heavily influenced by the activity of certain enzymes of Cytochrome P450. Different isosymes of said cytochrome play roles in demethylating Codeine (3-Methlymorphine), making it a prodrug for the delivery of Morphine. There are a wide range of medications, foods and dietary supplements that effect the functioning of these enzymes.
If you can get back to us with more information regarding what exactly you consume on a regular basis, maybe we can give you a better answer.