Say, I'm curious! How did you work out/decide on Zurg having become a thread before the Galactic Alliance was established? I don't recall there being any mention about when exactly Zurg became a threat. Was it mentioned in one of the episodes?
Well, the thing is, having a wikia is not about making estimates, it's about giving accurate information. So since we canot say for certain whether the GA was made in response to Zurg, or whether Zurg emerged after the GA was initially formed, it would be misleading to suggest or imply that either one or the other is fact. So while kudos for making a graph, which I really like! It would be best to be either more general in said graph or not have said graph altogether. Or, to not add when/where Zurg comes into play in said graph. ^^
Well, I figured it was somewhere between those purple lines, since he would have had to have become a threat before Tangea joined (since the Galactic Alliance knew about him) but when exactly he became a known threat wasn't really ever made clear...although I'm pretty sure it was loooong after Natron was overthrown (since that was ancient times)
If you look, the two purple lines are fairly far apart, so it's not specific to a certain point in time.