27,911 posts were deleted on Server Fault during the past 365 days (query run on Feb. 16th, 2016). That breaks down as follows:
Post Type Deleted by... Posts Deleted % of total
--------- -------------------------------------------------------- ------------- ----------
Question Auto-deletion: AbandonedClosed 6105 21.87 %
Question Author vote 3776 13.53 %
Answer Moderator 3220 11.54 %
Question Auto-deletion: AbandonedQuestions 2955 10.59 %
Question Moderator 2035 7.29 %
Question Auto-deletion: DeadQuestions 1777 6.37 %
Answer Parent question deleted (Moderator) 1657 5.94 %
Question Auto-deletion: MigrationStubs 1374 4.92 %
Answer Author vote 1172 4.20 %
Answer Converted to Comment 1166 4.18 %
Answer Parent question deleted (Auto-deletion: AbandonedClosed) 998 3.58 %
Answer Parent question migrated 526 1.88 %
Answer Spam/Offensive flags 239 0.86 %
Answer Parent question deleted (Author vote) 226 0.81 %
Answer Parent question deleted (3rd-party vote) 173 0.62 %
Question 3rd-party vote 116 0.42 %
Question Spam/Offensive flags 76 0.27 %
Answer Parent question migration rejected 65 0.23 %
Question Author was deleted 60 0.21 %
Answer Author was deleted 59 0.21 %
Answer Review 48 0.17 %
Answer Parent question deleted (Author was deleted) 31 0.11 %
Answer Parent question deleted 28 0.10 %
Answer 3rd-party vote 16 0.06 %
Answer Parent question deleted (via Vote) 10 0.04 %
Answer Parent question deleted (Spam/Offensive flags) 2 0.01 %
Answer Parent question deleted (Auto-deletion: MigrationStubs) 1 0.00 %
Note that during this same time period, 83,140 posts were created.
This looks only at posts that were deleted during this time period and remain deleted. It does not count posts that were deleted and then undeleted, nor does it double-count those that were deleted, undeleted, and then re-deleted. There are arguments to be made for counting all of these things, but they are few in number and mostly just add confusion.
##See also: Rules for auto-deletion