| Value | Category | Cases | |
|---|---|---|---|
| 0 | <12 months | 300 |
8.6%
|
| 1 | 1 year | 168 |
4.8%
|
| 2 | 2 years | 489 |
14%
|
| 3 | 3 years | 677 |
19.3%
|
| 4 | 4 years | 420 |
12%
|
| 5 | 5 years | 812 |
23.2%
|
| 6 | 6+ years | 373 |
10.7%
|
| 7 | non-numeric | 25 |
0.7%
|
| 8 | don't know | 235 |
6.7%
|
| 11 | .Z | 4733 |