CREATE TABLE table_67346 ("Poll source" TEXT, "Date ( s )  administered" TEXT, "Sample size" TEXT, "Margin of error" TEXT, "Jerry Brown  ( D ) " TEXT, "Meg Whitman  ( R ) " TEXT)

How many people were surveyed in the poll from June 30, 2010?
SELECT "Sample size" FROM table_67346 WHERE "Date(s) administered" = 'june 30, 2010'
SELECT "Sample size" FROM "table_67346" WHERE "Date(s) administered" = 'june 30, 2010'