The former used to be the case, but I quickly corrected it so that the latter is true; this is one of the reasons that the activity is only calculated once per day: it has to cycle through each day in the past 28 days and count posts to work properly.

This does mean that people like me that only access from work (at a 8-5 M-F desk job) can never rise above 71%, but hey, that's an accurate reflection of my activity.