Table schema:
CREATE TABLE document_functional_areas (document_code VARCHAR, functional_area_code VARCHAR); CREATE TABLE documents (access_count INTEGER, document_code VARCHAR); CREATE TABLE functional_areas (functional_area_code VARCHAR, functional_area_description VARCHAR)

Question: Find the average access counts of documents with functional area "Acknowledgement".
SQL: SELECT AVG(t1.access_count) FROM documents AS t1 JOIN document_functional_areas AS t2 ON t1.document_code = t2.document_code JOIN functional_areas AS t3 ON t2.functional_area_code = t3.functional_area_code WHERE t3.functional_area_description = "Acknowledgement"