You know the answer. 100%

Once you finish researching gold means nothing anymore. Then it can go back to 0%

How can you run 100% and not lose population? Comforting (disaster relief) every 25 minutes.
All you need is a decent food production and a decent size population. Just remember to reset the rate before you log off, or all the hard work will be for nothing.
If the server crashes, I take no responsibilty for the damage done, that's the risk you take.