i would like to address the word "mean", and add a bit of caution. in our society, we generally look for a quick fix on meaning; something means this, but not that. what does that scientific study mean? what does that court order mean? we think of meaning as the bottom line. yet meaning is a process of gaining understanding, and it is much more subtle than a bottom line. your question potentially suggests that there is a single meaning to any of the events or charts you describe, and there are in truth many, and many layers.
in fact, your question is a fine place to begin the entire study 