Figure 13. Retrospective analysis (starting in 2000 and proceeding back to 1995) of average F (4-8, unweighted) with F on the oldest age (9) derived by setting F9 equal to F8 (top left), F7-8 (top right), F6-8 (middle left), F5-8 (middle right), F4-8 (bottom left), and F3-8 (bottom right).