Thanks for the answer. But it doesn't work for me. I included a savegame if that helps.
Neither by tooltip nor the real decay per turn I see a difference between city states with trade routes or without.
Maybe it is because I play only with the Community Patch, but not together with the Balance Patch?
.
EDIT:
That savegame is from the January 9th version, which doesn't seem to be compatible (crash to desktop) with the latest version.
If you are using the CP, but not the CBP, you need to download Whoward's enabler mod for CSD (the CP follows the same restrictions as Whoward's combined DLL) (http://www.picknmixmods.com/mods/a12c1ffc-58c4-4197-bc12-320533ecee53/mod.html
G