This graph shows the historic failure rates -- at a per-week granularity -- for any test method that has failed in the past 7 days. Each test method that has had any failures in the past 7 days is displayed as a unique "series" (ie: line) in the graph.
Note: because suite level failure rates are inheriently not very reliable (due to Jenkins/JUnint reporting limitations) suite level failures are not included in this graph.
If a particular series is "Locked" (indicated in the pulldown) then moving the mouse over the graph will update the legend with the exact Failure Rate % for the given week the mouse is hovering over. Series can be locked/unlocked either by using the pulldown, or by single clicking on the graph -- which will lock the nearest (highlighted) series if no series is currently locked.
You can click-and-drag either horizontally or vertically to "Zoom" the graph along one axis. To Reset the zoom level double-click anywhere on the graph (Unfortunately if a series is locked, this will unlock it -- I haven't found any easy way to prevent that)
The raw data used to generate this graph can be downloaded as a CSV file.