text: Below is an context that describes a sql query, paired with an question that provides further information. Write an answer that appropriately completes the request.  # noqa: E501
  ### Context:
  CREATE TABLE museum (num_of_staff INTEGER, open_year INTEGER)
  ### Question:
  Find the average number of staff working for the museums that were open before 2009.
  ### Answer:
  SELECT AVG(num_of_staff) FROM museum WHERE open_year < 2009