user: Question: What is the average ERP W for callsign K207BK?
Columns: ['Call sign', 'Frequency MHz', 'City of license', 'ERP W', 'Class', 'FCC info']
Types: ['text', 'real', 'text', 'real', 'text', 'text']
Sample row: ['K208DQ', 89.5, 'Almont, Colorado', 16.0, 'D', 'FCC']
SQL:

assistant: SELECT AVG("ERP W") FROM "Table" WHERE "Call sign" = 'K207BK';