Rudimentary statistics tells us that the probability of this happening are the failure rate to the power of 11 ...
If we assume that this was a 1/10,000,000 situation we could calculate the appropriate failure rate by taking 0.0000001 to the 11th root ... this gives us a value of 23.1%
If the failure rate was 10% (high but reasonable) there would be a 1/10,000,000,000 chance of having 11 failures of a system ...