Hey Mirko. Someone once did the calculations. It was a long time ago, possibly even last year, posted in either the MP or Strategy Forums. Short of either that person reading this or you trawling through the archives, I'm not sure how you'd find them. The game level, though, is certainly a factor.
The only contribution I can make is a table from "Civ 2- The Official Strategy Guide", a book published a couple of years ago by a Microprose insider. It only teases rather than really explains anything, as follows:
Science Increment - the modifier used to help determine how many Science light bulbs are required to discover the next Advance:
Chief 6
Warlord 8
Prince 10
King 12
Emperor 14
Deity 14*
*On Deity level, this number may be adjusted + or - 1, depending on how far ahead or behind you are in research.
Best I can do. Sorry.
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