Which Percent of Slovenes 1951 has a Number of people 1991 larger than 8, and a Village (German) of plöschenberg?
CREATE TABLE "references" (
  "village_german" text,
  "village_slovenian" text,
  "number_of_people_1991" real,
  "percent_of_slovenes_1991" text,
  "percent_of_slovenes_1951" text
);
SELECT "percent_of_slovenes_1951" FROM "references" WHERE "number_of_people_1991">8 AND "village_german"='plöschenberg';