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?
CREATE TABLE "current_individual_rankings" (
  "location_state_city" text,
  "usn_2013" real,
  "bw_2013" real,
  "forbes_2011" real,
  "ec_2013" real,
  "ft_2011" real,
  "ae_2011" real,
  "cnn_2011" real,
  "bi_2013" real,
  "arwu_2012" real
);
SELECT AVG("arwu_2012") FROM "current_individual_rankings" WHERE "usn_2013"<91 AND "location_state_city"='illinois, champaign' AND "ec_2013">1000;