CREATE TABLE table_42871 ("Year" FLOAT, "Competition" TEXT, "Venue" TEXT, "Position" TEXT, "Event" TEXT, "Notes" TEXT)

Which Year has a Competition of olympic games, and a Venue of atlanta, united states?
SELECT AVG("Year") FROM table_42871 WHERE "Competition" = 'olympic games' AND "Venue" = 'atlanta, united states'
SELECT AVG("Year") FROM "table_42871" WHERE "Competition" = 'olympic games' AND "Venue" = 'atlanta, united states'