CREATE TABLE table_78034 ("Source" TEXT, "Date" TEXT, "Cardwell" TEXT, "Jones" TEXT, "Knight" TEXT, "Lanier" TEXT, "Martin" TEXT)

What source has a cardwell of 20%?
SELECT "Source" FROM table_78034 WHERE "Cardwell" = '20%'
SELECT "Source" FROM "table_78034" WHERE "Cardwell" = '20%'