task
Essentially, count the number of occurrences of =={{header| on each task page.

Output:

100 doors: 20 examples.
99 Bottles of Beer: 29 examples.
Abstract type: 10 examples.

Total: X examples.
For a full output, updated periodically, see Rosetta Code/Count examples/Full list.

You'll need to use the Media Wiki API, which you can find out about locally, here, or in Media Wiki's API documentation at, API:Query

TaskList = Flatten[
   Import["http://rosettacode.org/wiki/Category:Programming_Tasks", "Data"][[1, 1]]];
Print["Task \"", StringReplace[#, "_" -> " "], "\" has ", 
  Length@Select[Import["http://rosettacode.org/wiki/" <> #, "Data"][[1,2]], 
  StringFreeQ[#, __ ~~ "Programming Task" | __ ~~ "Omit"]& ], " example(s)"]& 
  ~Map~ StringReplace[TaskList, " " -> "_"]