Sum as Annotation, Include "Previous Period"
I am using Charts to track "direct" sales of my app. Other sales charts, like those featured on Stripe's dashboard or Mac App Store, feature a sum and "previous period" metric that quickly shows you how much sales are up/down for a given period. See attached.
AdminTom (Product Manager, MongoDB) commented
Thanks Caylan - this is definitely on our radar - will probably look at Number and Gauge charts first, and then consider how to apply it to other charts later.