Please read the following table in Markdown format and then answer the question according to the table. Table cells in one row are seperated by '|', and different rows are seperated by '
'.

Table:
| Period | Civilians | Security forces | Insurgents | Total per period |
| --- | --- | --- | --- | --- |
| 1996.0 | N/A | N/A | N/A | 156.0 |
| 1997.0 | 202 | 44 | 102 | 348.0 |
| 1998.0 | 118 | 42 | 110 | 270.0 |
| 1999.0 | 115 | 36 | 212 | 363.0 |
| 2000.0 | N/A | N/A | N/A | 50.0 |
| 2001.0 | N/A | N/A | N/A | 564.0 |
Question:
How many insurgents are there when the total per period is 156?
Answer:
N/A