Questions about long term storge: lifespan and salt levels

[c.s.]

I have two questions:
1) What is the life span of sauerkraut? I realize that this is probably influenced by varying factors such as salt content and storage conditions. But I wanted to get an idea of the range that I can expect?

I recently had some sauerkraut at a potluck that was over a year old. It was a little mild (not that vinegary) but it got me excited about sauerkraut as a "survival food" (something with long storage life, simple to make, is nutritious and doesn't require any special care - like refrigeration). Any experiences or historical information?

2) What is the proper ratio of salt to use in kraut that I would want to just put in a bucket for storage and not deal with for awhile?

I've been using low amounts of salt when making my kraut. I try to use the mineral in moderation but am willing to use more for kraut that I want to squirrel away for hard times.