What would be the shelf life of a 1999 Cabernet sauvignon?

More information is required before a realistic recommendation can be made.
Like the region and producer of the wine.

Bear in mind a cheap mass produced wine won't last as long as one from a more expensive, good producer. Also the storage conditions play a major role as well.
Simply stored upright on the kitchen side will destroy a wine rapidly.
Whereas the optimum conditions would be advantageous for a long life.