Mead at 4 Weeks

In typical OCD fashion, I have taken daily measurements of fermentation rate (bubbles per minute) of the mead sitting in the corner of my home office.  Today is exactly 4 weeks since the start.  The rate this morning was 3.2 bubbles per minute.  So, the fermentation is still chugging along.  I thought it would have finished by now!  (Could this be a case of "a watched pot never boils"?)

Mead primary fermentation at 4 weeks
(It doesn't look any different to the Day 16 pic.)