Round Years No. X-rayed Category 1 Category 2+ All Categories
      No. Prevalence No. Prevalence No. Prevalence
1 1959-63 462999 32608 7 23401 5 56009 12.1
3 1969-73 238759 16389 6.9 7888 3 24277 10.2
5 1978-81 198055 6256 3.2 1902 1 8158 4.1
7 1986-89 76802 453 0.6 65 0.1 518 0.7
8 1990-93 36970 138 0.4 10 0.01 148 0.4
9 1994-97 6378 13 0.2 0 0 13 0.2
  1998-2000 4647 26 0.6 9 0.2 35 0.8
Table 1: Categories of miners.