user: Question: What was the average total for the player from the United States, who won in 1978?
Columns: ['Player', 'Country', 'Year(s) won', 'Total', 'To par', 'Finish']
Types: ['text', 'text', 'text', 'real', 'text', 'text']
Sample row: ['Jack Nicklaus', 'United States', '1962 , 1967 , 1972 , 1980', 280.0, 'E', 'T6']
SQL:

assistant: SELECT AVG("Total") FROM "Table" WHERE "Country" = 'United States' AND "Year(s) won" = '1978';