You can now chart Max CPC as a metric in the performance summary graph. This gives you a great visual representation of a keyword’s bids over time, and you can also compare the bids with any other metric of your choice.
To chart a bid history:
Go to a Keywords page in the UI.
Select one keyword in the statistics table, and click Filter to selected keywords.
In the upper righthand corner of the performance summary graph, select Max CPC as a metric.
You may also want to select a second metric like Cost, so you can see how cost correlated with your bids over time.
Bids can change several times a day, and we chart all of those changes. For example, if the bid changes 10 times in a day, the graph charts them all as 10 different points with related time markers. Hovering over the bid change tickers in the graph shows you the new bid value and exact time of the bid. However, because other metrics (such as cost, clicks, and actions) are only recorded daily, those are charted at a daily frequency.