Doesnt look as if it has lasted. Or do you mean, how long till it blows out? Looks like duff tyre or the suspension doesn't work.
Replace it now, it is just a worn tyre, worn thru the tread rubber in fact, I've seen this with Dunlops, Avons, Pirelli's, and Michelins. It doesn't take very long at all to go from a normal looking "low" tyre to a totally knackered one like this! (just for reference, I used to work in a garage that supplied and fitted Michelin tyres)