How many TFR were there in 2006 when the GFR was 53.8?
CREATE TABLE "references" (
  "county" text,
  "live_births_2006" real,
  "gfr_2006" text,
  "tfr_2006" text,
  "whites_as_pct_of_pop" text
);
SELECT "tfr_2006" FROM "references" WHERE "gfr_2006"='53.8';