Time Centre-R Centre-S Centre-T
  drug1 drug2 drug3 drug1 drug2 drug3 drug1 drug2 drug3
1 0 0 0 0 0 0 0 0 0
2 1 1 0 0 0 2 0 3 3
3 2 3 0 1 0 2 3 4 3
total 3 4 0 1 0 4 3 7 6
total   7     5     16  
Table 1: Numbers of dropouts in the multi-centre trial.