user: Question: How many casualties were from the IED circumstance?
Columns: ['Date', 'Location', 'Nature of incident', 'Circumstances', 'Casualties']
Types: ['text', 'text', 'text', 'text', 'text']
Sample row: ['2010-01-28', 'Chahar Darreh District', 'Hostile', 'Direct fire', '1 WIA']
SQL:

assistant: SELECT COUNT("Casualties") FROM "Table" WHERE "Circumstances" = 'IED';