CREATE TABLE table_name_96 (est VARCHAR2, league VARCHAR2, state_province VARCHAR2, city VARCHAR2)

In what year was the NFL team in chicago illinois established?
SELECT est FROM table_name_96 WHERE state_province = "illinois" AND city = "chicago" AND league = "nfl"
SELECT "est" FROM "table_name_96" WHERE "chicago" = "city" AND "illinois" = "state_province" AND "league" = "nfl"