Suppose that among women who are age 50–74, 22% are age 50–54, 21% are age 55–59, 20% are age 60–64, 19% are age 65–69 and 18% are age 70–74. What is the overall 1-year cumulative incidence among Caucasian women ages 50–74? 

Cancer
The SEER Cancer Registry [18] is an important resource for estimating cancer incidence rates and documenting changes in incidence rates over time. Cancer cases are accumulated over 17 cancer registries and are converted to cumulative incidence rates by dividing by U.S. Census population estimates within specific age-groups. The following data were obtained for breast cancer 1-year cumulative incidence rates for Caucasian women of age 50–74 from 1995 to 2000 (period A).

Table 3.19 Breast cancer 1-year cumulative incidence rates by age among Caucasian women age 50–74, SEER, 1995–2000 (period A)

Age group             1-year cumulative incidence per 100,000 women+
50–54............................................................................................360
55–59............................................................................................422
60–64............................................................................................479
65–69............................................................................................534
70–74............................................................................................600