I'm looking for a general word. A few examples to help illustrate:
- If a class has 10 spots and 4 people have registered, the class' ____ is 4.
- If you're filling up a container of unknown capacity and it takes a while and someone asks on your progress, they may inquire about the container's current ____.
- If a battery or capacitor is 50% charged, its ____ is half.
- If a progress meter or a loading indicator hasn't progressed very far, its ____ is low.
The closest I've come up with is "fullness" (or "level" in the container example, though that's usually used along with a reference to the thing filling the container, as in "water level" or "the level of the dirt"). But those don't seem quite right. I think something more generic that could be used in these and other similar cases is what I'm after - any place you have a total and you're after the current amount filled, whether or not the total or the current amount are specific numbers or general amounts (like nearly empty or nearly full).
A closely related word to content might be proportion. But this doesn't capture the specific emphasis on "how close to complete fullness" I'm after, although it does speak to the relation of the part to the whole, which is an essential element.