Don't forget the <rating history></rating history> too. Because remember that anyone can change their ratings at any time. If you don't, then there will be no record of what happened.
Rate with numbers
Although it is not a bad tactic to keep the rate history, It is not a priority. Because those ratings have to do with individuals.
The vote history on the other hand it is important to be kept, because the vote refers to the whole community (and not to individuals).
It is important to keep the vote history of the community, because the decisions the community takes are not irrelevant eachother, they depent eachother.
Here follows an example of interdependant votes:
Vote1:Lets go to bed (yes/no/other)
Vote2:Lets wear our shoes (yes/no/other)
It is important to keep the history of the above votes, because if we vote "yes" to the Vote1, in the same time we have to vote "no" in the Vote2. And this can be seen in the vote history. So the vote history shows whether the community is a logical community, or a community of fools.
So when we keep the vote history, we preserve the consistency of the decisions of the community. And also, whithin the examined time frame, we can say whether someone's actions were against the will of the community or not.