| Duration | Frequency | Percentage |
| <6 months | 18 | 18.6% |
| 6 months to 1 year | 37 | 38.1% |
| >1 year | 42 | 43.3% |
| Total | 97 | 100.0% |
| <6 months | 18 | 18.6% |
| 6 months to 1 year | 37 | 38.1% |