user: Question: When 30% is scott mcadams (d) percentage how many poll sources are there?
Columns: ['Poll source', 'Dates administered', 'Joe Miller (R)', 'Lisa Murkowski (R) write-in candidate *', 'Scott McAdams (D)']
Types: ['text', 'text', 'text', 'text', 'text']
Sample row: ['Public Policy Polling', 'October 30–31, 2010', '37%', '30%', '30%']
SQL:

assistant: SELECT COUNT("Poll source") FROM "Table" WHERE "Scott McAdams (D)" = '30%';