Table 4.

PLCO and LSS participants in tracing by study year^a

Year	PLCO N=154,901		LSS N=34,614
	Number in tracing	Percent of number randomizedb	Number in tracing	Percent of number randomizedc
2002	2787	1.8	Recruitment incomplete	-
2003	2372	1.5	Recruitment incomplete	-
2004	1700	1.1	Recruitment incomplete	-
2005	1218	0.8	64	0.2
2006	909	0.6	184	0.5
2007	743	0.5	178	0.5
2008	730	0.5	167	0.5
2009	567	0.4	16	0.0
2010	Not available	-	27	0.1

^a2006 data for UCD were unavailable. Instead, the average of numbers in tracing in 2005 and 2007 was used. Tracing is defined as having no ASU for two years in a row.

^bDenominator for calculation is 154,901 (number of PLCO participants randomized)

^cDenominator for calculation is 24,614 (number of LSS participants randomized)