CREATE TABLE table_20799587_1 (obama_number INT, mccain_percentage VARCHAR)

How many people voted for Obama in the county where McCain got 72.75% of the votes?
SELECT MIN(obama_number) FROM table_20799587_1 WHERE mccain_percentage = "72.75%"
SELECT MIN("obama_number") FROM "table_20799587_1" WHERE "72.75%" = "mccain_percentage"