Name the total number of year named for  athena , greek goddess of wisdom .
CREATE TABLE "tesserae" (
  "name" text,
  "latitude" text,
  "longitude" text,
  "diameter_km" text,
  "year_named" real,
  "name_origin" text
);
SELECT COUNT("year_named") FROM "tesserae" WHERE "name_origin"='Athena , Greek goddess of wisdom .';