| Disease/symptom | Year 1993 | Year 2002 | Year 2007 | Year 2014 | p for trend |
| Asthma [%] | 3.4 | 4.8 | 8.6 | 12.6 | 0.00001 |
| Obstructive bronchitis [%] | 8.5 | 21.2 | 15.1 | 15.1 | 0.04 |
| Chest wheeze current [%] | 12.3 | 14.6 | 15.1 | 12.1 | 0.7 |
| Dyspnea current [%] | 3.9 | 5.9 | 7.0 | 7.3 | 0.0005 |
| Exercise induced wheeze [%] | 2.0 | 2.2 | 4.2 | 6.1 | 0.00001 |
| Exercise induced dyspnea [%] | 2.1 | 3.7 | 4.9 | 5.9 | 0.00001 |
| Exercise induced cough [%] | 7.5 | 10.6 | 19.9 | 19.0 | 0.00001 |