CREATE TABLE table_204_576 (id DECIMAL, "year" DECIMAL, "best" TEXT, "location" TEXT, "date" TEXT, "world rank" TEXT)

what year was the worst time given ?
SELECT "year" FROM table_204_576 ORDER BY "best" DESC LIMIT 1
SELECT "year" FROM "table_204_576" ORDER BY "best" DESC NULLS LAST LIMIT 1