user: Question: What is the sum of To Par, when Country is "United States", and when Year(s) Won is "1973"?
Columns: ['Player', 'Country', 'Year(s) won', 'Total', 'To par', 'Finish']
Types: ['text', 'text', 'text', 'real', 'real', 'text']
Sample row: ['Hale Irwin', 'United States', '1974', 288.0, 4.0, 'T4']
SQL:

assistant: SELECT SUM("To par") FROM "Table" WHERE "Country" = 'United States' AND "Year(s) won" = '1973';