I'm just curious if there is such a statistic available anywhere?
If you know the query, you could use the Query site
You could sum the number of upvotes and group that by hour. That would give a rough image of the reputation given.
A good statistic would then create a different list of if it's a question or an answer being upvoted and multiply the number by the reputation it gives, and then look at the downvotes and reduce the number by those results.
Here's a naive query. You could take those results and plot them.
I ran it and charted it for you, just if you were curious.
Warning, big png image.