If you are going to be really accurate you've also got to factor out all issues external to the airline, from the obvious ATC/navaids quality/provision to the absurd, such as the water buffalo that wandered onto the Aceh rw and pranged a 73 in the last few hours.
You could go further and factor out all/some weather issues. By way of example the F104 operated by USAF in Germany had an appalling safety record, largely due to the fact that the pilots had trained in weather-free Arizona/Nevada.
Only when you are comparing real like with like can you give a true "airline safety" league.