Below is an context that describes a sql query, paired with an question that provides further information. Write an answer that appropriately completes the request.  # noqa: E501
### Context:
CREATE TABLE table_21636599_2 (insurgents VARCHAR, total_per_period VARCHAR)
### Question:
How many insurgents are there when the total per period is 156?
### Answer:
SELECT insurgents FROM table_21636599_2 WHERE total_per_period = 156