Our last sighting so far was in April 2012 (data here).
This was the first time we saw Hail Mary Cloud style attempts at accessing OpenBSD systems.
The majority of attempts were spaced at at least 10 seconds apart, and until I revisited the data recently, I thought only two hosts in China were involved.
In fact, 23 hosts made a total of 4757 attempts at 1081 user IDs, netting 0 successful logins.
(2012-04-06) If We Go One Attempt Every Ten Seconds, We're Under The Radar (slashdotted) - the article has been corrected with proper data extracted.