SELECT year_opened FROM track WHERE seating BETWEEN 4000 AND 5000
Show year where a track with a seating at least 5000 opened and a track with seating no more than 4000 opened.
[Schema (values) (types)]: | race_track |  race : race_id (text) , name (number) , class (text) , date (text) , track_id (text) | track : track_id (text) , name (number) , location (text) , seating (text) , year_opened (text);