How to view the ranking history for a specific keyword
To get started, head to the campaign of your choosing, then hover over the sidebar on the left, click SEO to expand, then Rank Tracker.
Now on the Rank Tracker page, select the date range you'd like to view historical keyword data for. This can be done using the date picker in the upper right of Rank Tracker. Click Apply to update the date range.
Next, scroll down to the keyword table, and click on the keyword for which you wish to see the ranking history.
This will open a slide-out on the right side of the page, showing a line graph at the top, and a table of historical rankings below.
The data shown is dependent on the date range selected. If last week is the date range, then the previous weeks 7 days of keyword history will be displayed.
In order to display historical data, the metrics you select must have been enabled for the time period selected, as well. For example, if you weren't historically tracking Bing, then enabling it now will not display any data.
You can view additional historical data by clicking the Settings icon in the slide-out, then selecting from the available metrics which ones you'd like to see historical data for.