No use trying to force me guys - because of that I will not release a spreadsheet for v.0.79.5...........
J/K
Actually a new patch should land on the DyP site within 24 hours (after that I'm on vacation for 5 days, so it's now or never.... well never as in never in the next five days anyway)
If that fails, I will upload the 0.79.5 reference, don't worry.
Dingocat85: Decreasing happiness over time is unfortunately not possible for Improvements

The idea is not bad though, but we need Firaxis (the guys working on the engine, remember

) to allow it first.
The other idea is definitely good thinking - Don't know if we will implement it yet, as we really would prefer an improvement to go obsolete at the same time all over the empire (specifically the Slave Market going obsolete with Emancipation) - but still very good thinking

(I may just implement it in my own mod - which will be out in the year 2525)