Text: 6 per 996 from 2001 to 2012 = 0.00602 = 0.6% from 2001 to 2012

The four people who were known to have lung cancer in 2001 were not at risk, so they are excluded from the denominator. Among the remaining 996 people at risk, there were 6 new cases during the observation period, so the cumulative incidence was 6/996 or 0.6% from 2001 to 2012.