SELECT
  ROUND(AVG(TOTAL_VALUE), - 1) 
FROM
  ( 
    SELECT
      TOTAL_VALUE 
    FROM
      CONVENIENCE 
    WHERE
      SURVEY_YEAR = '2019' 
      AND KIND_CODE = '100' 
    ORDER BY
      TOTAL_VALUE 
    LIMIT
      2 - ( 
        SELECT
          COUNT(*) 
        FROM
          CONVENIENCE 
        WHERE
          SURVEY_YEAR = '2019' 
          AND KIND_CODE = '100'
      ) % 2 OFFSET ( 
        SELECT
          (COUNT(*) - 1) / 2 
        FROM
          CONVENIENCE 
        WHERE
          SURVEY_YEAR = '2019' 
          AND KIND_CODE = '100'
      )
  )