You can run a graphical report showing your Ranking History for each keyword targeted since you started your campaign.
To do this log into your campaign. Click View This Campaign/All Keyword Rankings.
On your Rankings Report click on the ranking you want to see charted. For instance, if you rank #1 on Google for a keyword this week, you can click on that ranking and a graphical report showing your Ranking History for that keyword since you started your campaign for that word will appear.