Instruct: What is the average ARWU 2012 ranking of Illinois, Champaign, which has a USN 2013 ranking less than 91 and an EC 2013 ranking larger than 1000?
Output: SELECT AVG ARWU 2012 FROM table WHERE USN 2013 < 91 AND Location (State, City) = illinois, champaign AND Ec 2013 > 1000