Education vs Defense of Marriage
The circles represent states that had (at the time the data was sourced) voted on defense of marriage amendments to their constitution that would ban same-sex marriage (but not necessarily passing them). The vertical axis represents a state's education index, while the horizontal axis represents its votes in favor of the amendment.
Note the downward trend.
This data comes from StateMaster, and the graph is theirs, not mine. The site generates lists or graphs comparing whatever data you select.