Table 1. Characteristics of study subjects.

	1993–1998		1999–2001		2002–2006		Total
	Number	%	Number	%	Number	%	Number	%
Sex
Male	2,817	82.2	2,501	81.2	3,639	82.6	8,957	82.1
Female	610	17.8	579	18.8	765	17.4	1,954	17.9
Age, years
≤64	1,093	31.9	842	27.3	1,169	26.5	3,104	28.4
65–74	1,469	42.9	1,341	43.5	1,770	40.2	4,580	42.0
≥75	865	25.2	897	29.1	1,465	33.3	3,227	29.6
Disease stage
Limited disease (LD)	1,482	43.2	1,369	44.4	1,756	39.9	4,607	42.2
Extensive disease (ED)	1,469	42.9	1,371	44.5	2,203	50.0	5,043	46.2
Unknown	476	13.9	340	11.0	445	10.1	1,261	11.6
Total	3,427	100.0	3,080	100.0	4,404	100.0	10,911	100.0