Frequencies for first 10,000 rows of castage variable in namcs2012 dataset :

Type of cancer |      Freq.     Percent        Cum.
---------------+-----------------------------------
         Blank |         12        0.12        0.12
 Unknown stage |        394        3.94        4.06
Not applicable |      9,450       94.50       98.56
       In situ |         44        0.44       99.00
       Stage I |         45        0.45       99.45
      Stage II |         17        0.17       99.62
     Stage III |         16        0.16       99.78
      Stage IV |         22        0.22      100.00
---------------+-----------------------------------
         Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 28 Mar 2016