Frequencies for first 10,000 rows of chmthrpy_srvc_cd variable in pos2005 dataset :

       srv: |
chemotherap |
  y service |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      8,731       87.31       87.31
          0 |      1,255       12.55       99.86
          1 |         12        0.12       99.98
          2 |          1        0.01       99.99
          3 |          1        0.01      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 17 May 2017