I understand the reputation system, it works, among other things, as a reward to those who contribute.

I also tend to think of reputation also as a measure of value created by M.SE; when I gain a reputation, it is because I provided a 'service' to someone who values that service. With this, the sum of the reputation created on M.SE measures (approximates) the value created by M.SE.

Is there a statistics about the the sum of the reputation? How it varies with time? What are the peak hours/days/month? Is there a statistics across different SE sites?