what is the minimum norwegian americans (1980) where state is rhode island
CREATE TABLE "norwegian_americans_by_state" (
  "state" text,
  "norwegian_americans_1980" real,
  "percent_1980" text,
  "norwegian_americans_1990" real,
  "percent_1990" text,
  "norwegian_americans_2000" real,
  "percent_2000" text,
  "norwegian_americans_2009" real,
  "percent_2009" text
);
SELECT MIN("norwegian_americans_1980") FROM "norwegian_americans_by_state" WHERE "state"='Rhode Island';