What is every value for % 20-39 if % 0-19 is 21,11%?
CREATE TABLE "external_links" (
  "neighbourhood" text,
  "pct_0_19" text,
  "pct_20_39" text,
  "pct_40_59" text,
  "pct_60_74" text,
  "pct_75" text
);
SELECT "pct_20_39" FROM "external_links" WHERE "pct_0_19"='21,11%';