Sample year   1987 p 1997 p 1997 p 1987 Age group, years 50-60   50–60   60–70   60-70 ≤10 mm n=10 n.s. n=33 n.s. n=30 <0.05 n=16   13.6%   18.6%   24.8%   13.3% 10–20 mm n=32 n.s. n=90 n.s. n=61 n.s. n=50   43.2%   50.8%   50.4%   41.7% >20 mm n=32 0.06 n=54 n.s. n=30 0.001 n=54   43.2%   30.6%   24.8%   45.0% Σ n=74   n=177   n=121   n=120 n.s., not significant

Table 3: Distribution of three tumor size intervals of two age groups in 1997.