The report card seems to only show data for the past month. Is there something I could check to verify if there was an overall drop in reader traffic over the last week?

The reason I ask is that Media Viewer actions seem to be dropping across the board since November 13th: http://multimedia-metrics.wmflabs.org/dashboards/mmv This trend is seen on all wikis. I'm trying to find the cause of this problem, because we're launching significant UI changes to all wikis today and we'll need to make sure that our EventLogging figures are accurate.