I find the exports from charts lacking. The export creates a separate worksheet for each object and doesn't evenly space time intervals.
I've attached "Performance Chart.xls" as exported from Virtualisation Manager (Chart -> Save Report -> Content -> Download).
After an hour of manipulation I've now got a sheet that I can work with ("Performance Chart - Consolidated.xls" also attached).
Please combine all objects from a report on the one page and make sure that the timeline is sequential.
(Similar to Edward Marshall's idea, but there doesn't seem to be a way to add attachments to comments)