Descriptive statistics of PIF values in different subgroups
| Subgroup | N Obs | Mean | Median | 10th Pctl | 90 Pctl | Min | Max |
| Asthmatic children | 60 | 47.19 | 47.93 | 28.59 | 63.09 | 12.83 | 74.10 |
| Adult ashmatics | 62 | 66.14 | 69.11 | 52.99 | 76.47 | 19.99 | 87.01 |
| Elderly asthmatics | 52 | 60.88 | 60.99 | 49.05 | 72.05 | 34.38 | 80.25 |
| COPD patients | 53 | 58.51 | 58.19 | 48.97 | 70.92 | 38.35 | 74.63 |