I was a system(Unix/Linux Admin) and Oracle admin (also DB2 & Informix)
I will give you a hint.
- If you work for Telecoms = a lot
- If you work for cash & carry = less
- If you work for a small family company = less
Another way to evaluate
- If there is an economic crisis like in Greece 2014 then = migrate to another area
- If the caws are fat = a lot