CREATE TABLE table_34518 ("Year" FLOAT, "Performance" TEXT, "World Ranking" FLOAT, "Venue" TEXT, "Date" TEXT)

How many world rankings are after Aug 5, 1980 ?
SELECT SUM("World Ranking") FROM table_34518 WHERE "Date" = 'aug 5' AND "Year" > '1980'
SELECT SUM("World Ranking") FROM "table_34518" WHERE "Date" = 'aug 5' AND "Year" > '1980'