human
Considering the provided database schema and associated query, produce SQL code to retrieve the answer to the query. 
###Database Schema: Track Name, Location, Length, Seating, Year Opened, Year Acquired [A ]
###Question: What is the year opened for Chicagoland Speedway with a seating smaller than 75,000?
gpt
SELECT AVG Year Opened FROM table WHERE Track Name = chicagoland speedway AND Seating < 75,000