all levels

Right. All levels of improvements ---- L1 through L3 infrastructure, naval bases and air bases; L1 through L5 industrial complexes and fortifications; as well as reactors and capitols ---- are included in the economic ranking points total. (Although not all levels of the same improvement have the same points associated with them.)

The tougher question is whether "repairs" to improvements count, too? Based on my personal experience, it appears that repairs sometimes are included, and sometimes they are not. If anyone has a definitive explanation, I'd love to hear it.

I am currently playing in a slow-moving "friendly" game, where I am producing more resources than I can expend on a daily basis, so I have used this opportunity to make extensive repairs of virtually all damaged buildings I inherited when I captured an entire country. The repaired buildings cover a full range of building types and levels, so it's a good sample. That said, I have been tracking the points awarded for building construction, and absolutely no points are awarded for the repair of the partially damaged level of a given building, i.e., L4 fortifications were 50% damaged and no points were awarded for restoring L4 fortifications to 100% completion. However, points were awarded for completion of the next level of the previously damaged building, i.e., L5 fortifications. It appears that you must be responsible for 100% of the construction of a given building level in order to receive credit for completing it.