Hi Jerry
They will last longer, the drier you store them.
Around 40% to 50% relative humidity, I would guess "2-3 years" with vigor and germination % declining in the third year. My house gets up to 50% RH, or a little over, much of the year.
If you want that big jar to stay viable as long as possible (15-25 years?) , you might put a packet of desiccant in it. I use a paper coin envelope with a tablespoon or so of fresh silica gel (which you can buy in a craft store, in the flower-drying isle). If you're concerned about over-drying the seeds, use less silica gel and also get a humidity-indicating card.
https://secure.drierite.com/ca...
http://www.uline.com/BL_1002/H...
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Seeds stay viable longest if dried all the way down to 15%-30% equilibrium RH. The length of time that seeds stay viable approximately doubles for every 10% reduction in their equilibrium relative humidity.
Kew Royal Botanical Gardens Millennium Seed Bank Project :
"Seed life span approximately doubles for every 10% reduction in seed eRH. "
http://www.kew.org/sites/defau...
http://garden.org/ideas/view/R...
http://garden.org/thread/view_...
