CREATE TABLE table_23763 ("Poll source" TEXT, "Dates administered" TEXT, "Joe Miller  ( R ) " TEXT, "Lisa Murkowski  ( R )  write-in candidate *" TEXT, "Scott McAdams  ( D ) " TEXT)

When 30% is scott mcadams (d) percentage how many poll sources are there?
SELECT COUNT("Poll source") FROM table_23763 WHERE "Scott McAdams (D)" = '30%'
SELECT COUNT("Poll source") FROM "table_23763" WHERE "Scott McAdams (D)" = '30%'