KW rating - do the 'points' gained accumulate?

Or does a KW start each day at 'zero' rating?

[KeepTrying]

I need a point about G to be clarified.
I understand how the position ranking of each ad. is determined by the relationship between CPC and the CTR.
What I want to know is this - after a period of time, is the 'slate' wiped clean for that KW?

Or does a high rating today, achieved by a high CTR, mean that the KW will also have a high rating tomorrow, next week, and next month?
In other words, does the KW gather a high rating on a day by day basis?

And what about KW that have been paused?
When its restarted, does the CTR rating revert back to zero?

Thanks.

[eWhisper]

The CTR for the KW formula weighs the last 1000 impressions a little higher than the overall CTR, but both are used in determining CTR for a keyword. So its best to have both a good historical CTR and last 1000 impression CTR. The slate is never 'wiped' clean, unless you delete the keyword all throughout your account, save everything, and then readd the keyword. ( [webmasterworld.com...] post 4)

When a keyword is unpaused, it's old data is saved and started from that point in time. So pausing a keyword only effects it's position if you have new competitors or existing competitors have changed their bids & CTRs.

[KeepTrying]

Thanks for that eWhisper, that answers my question perfectly,