Interesting question, but speaking of cans of worms...
You could ask the same question for other part of the 'travel experience' such as who do i fly, which equipment do they fly, where to/from/over, did the captain sleep well last night....
It is possible that certain patterns exist. Only two weeks ago researchers here published that Scottish people have a higher chance of dying on a Monday (I won't speculate on the causes here). Maybe the same happens with car accidents or train accidents or nuclear reactor accicents.
I agree, we should not be complacent and ask the questions - maybe someone has an answer, but be careful with the interpretation.

And fwiw: 1999 was one of the safest years on record: see Flight and AW.
Safe travelling