In how many different years did the race happen on February 27?
CREATE TABLE "table1_2241101_1" (
  "year" real,
  "date" text,
  "driver" text,
  "team" text,
  "manufacturer" text,
  "laps" text,
  "miles_km" text,
  "race_time" text,
  "average_speed_mph" text,
  "report" text
);
SELECT COUNT("year") FROM "table1_2241101_1" WHERE "date"='February 27';