Table 1. Number of participating Intensive Care Units (ICUs), number and percentage of medical ICU admissions for respiratory infections and gender and age distribution.
| Year | Participating ICUs | ICU patients with respiratory infections (%) | Gender, male (%) | Age, mean (SD) |
| 2003 | 33 | 750 (12.8) | 431 (57.5) | 63.82 (15.8) |
| 2004 | 36 | 778 (10.8) | 452 (58.1) | 63.00 (17.00) |
| 2005 | 45 | 1140 (12.8) | 657 (57.6) | 63.47 (15.8) |
| 2006 | 56 | 1585 (13.9) | 954 (60.2) | 63.84 (16.6) |
| 2007 | 62 | 1876 (12.9) | 1169 (62.3) | 64.14 (16.1) |
| 2008 | 68 | 2202 (13.4) | 1245 (56.5) | 64.46 (15.9) |
| 2009 | 77 | 2974 (14.1) | 1743 (58.6) | 64.43 (16.0) |
| 2010 | 81 | 3173 (13.4) | 1885 (59.4) | 64.84 (15.9) |
| 2011 | 85 | 3308 (13.6) | 1974 (59.7) | 64.19 (16.2) |