It seems that based on a recent Signpost article, another round of RfA reform has come into play. So here are my thoughts on becoming an admin, being an admin and ending adminship. The concepts are inter-related and should be considered together.
According to the stats, there are 703 active admins today. However, "active" means 30 edits in the past two months. By that statistic, there were 777 active admins on the 31 March 2011. It's interesting to note though, that on that date, there were only 107 admins on this list who made at least 1000 edits in a month. So yes, there are probably a few hundred active admins, but very active ones? (For comparison there were about 500 admins on the list, who had made 100 edits)
Perhaps this is because vistor base is falling? Not really - we've fallen from a peak of 2910 "very active" editors in 2006 (100 edits per in a given month) to 2440 in 2012.[1] That's a 16% fall. The total number of database changes has fallen by about 25%.[2] For comparison, the number of active admins fell during the period 2008 - 2011 by about 30%.[3] The number of RfA requests has fallen by 85%.[4]