60% probability of survival in 8 months

I bought on 14.12.2010 two 4GB sticks, two 8GB sticks and six on 21/12/2010 8 GB sticks.

In spring 2011, a 4GB flash drive died the heat death on a laptop.

In the summer I reported one of my nephew that his 8GB stick is no longer readable. Immediately afterwards complained my second nephew that his 8 GB flash drive no longer comes.

And today an 8GB stick adopted, which I had left. That reminds me, the problem of slight overheating of these sticks is known, I had already operated as a precaution it only to an extension cord. Nevertheless.

From a total of 10 sticks so have survived eight months through today only 6 sticks.

Addendum of 26/08/2011:
Numbers corrected (10, not 12 sticks). I beg your pardon.
2 of gave away sticks have not yet been properly exploited.
Overall, I expect a probability of survival at 1 year of less than 50%.