| Value | Category | Cases | |
|---|---|---|---|
| 1 | January | 4 |
4%
|
| 2 | February | 5 |
5%
|
| 3 | March | 1 |
1%
|
| 4 | April | 2 |
2%
|
| 5 | May | 2 |
2%
|
| 6 | June | 1 |
1%
|
| 7 | July | 1 |
1%
|
| 8 | August | 1 |
1%
|
| 9 | September | 20 |
20%
|
| 10 | October | 15 |
15%
|
| 11 | November | 27 |
27%
|
| 12 | December | 21 |
21%
|
| 13 | All year (operated every month) | 0 |
0%
|
| Sysmiss | 1972 |