I need to know the monthly gross salary for a job in Germany, it's urgent!!

Hello everybody.
I decided to move to Germany so I sent my curriculum to many companies for a job.
Can you help me about the average salary for a senior electronic designer with 30 years of working experience in Germany? I have several years of experience in the aerospace, railway, robotic fields and other sub-sectors.
I need to know the monthly gross salary because a company that I will have an interview asked me this. I must communicate it on Monday 19th December, before the interview.
Another question, how much is the total deduction from salary in percentage, more or less, considering retirement, health, taxes, etc. ... ?
The monthly salary paid in a year are 13, 14 or.... ?
Thank you very much to all for your answers.
Pino