Ask HN: Tool like Google Analytics to track keyword search ranking over time

Hi hackers,

We currently use Rank Checker toolbar (http://tools.seobook.com/firefox/rank-checker/) to track the search rankings for our site for certain keywords...

This works great, but is a manual process every time. Is there free tool that does the same but over time, eg graphing rankings each day, ala Google Analytics?

This would help us tons see how our SEO efforts are paying off (or not)

Thx..