From 1991/92 to 1994/95 there was an upward gradient in fibrosing alveolitis from 20 per million to 24 per million. After the change to ICD 10 the category expanded to 'Other interstitial pulmonary diseases with fibrosis' and there was a marked increase (40%) to 34 per million in 1995/96. The trend since then has continued upwards in adults.