• CREATE TABLE #Sample (MyStuff VARCHAR(22))

    INSERT INTO #Sample (MyStuff)

    SELECT '13/01/2010(DD/MM/YYYY)' UNION ALL

    SELECT '01/13/2010(MM/DD/YYYY)' UNION ALL

    SELECT '14/04/2001(DD/MM/YYYY)' UNION ALL

    SELECT '11/03/2002(MM/DD/YYYY)' UNION ALL

    SELECT '2010/01/01(YYYY/MM/DD)'

    SELECT RIGHT(MyStuff, 12), COUNT(*)

    FROM #Sample

    GROUP BY RIGHT(MyStuff, 12)

    “Write the query the simplest way. If through testing it becomes clear that the performance is inadequate, consider alternative query forms.” - Gail Shaw

    For fast, accurate and documented assistance in answering your questions, please read this article.
    Understanding and using APPLY, (I) and (II) Paul White
    Hidden RBAR: Triangular Joins / The "Numbers" or "Tally" Table: What it is and how it replaces a loop Jeff Moden