user: Question: What is the average Year, when Country is "U.S.", and when Location is "Edmond , OK"?
Columns: ['Perpetrator', 'Date', 'Year', 'Location', 'Country', 'Killed', 'Injured']
Types: ['text', 'text', 'real', 'text', 'text', 'real', 'text']
Sample row: ['Sanurip , 36', '04.15 April 15', 1996.0, 'Timika Airport', 'Indonesia', 16.0, '11']
SQL:

assistant: SELECT AVG("Year") FROM "Table" WHERE "Country" = 'U.S.' AND "Location" = 'Edmond , OK';