Frequencies for first 10,000 rows of chmthrpy_srvc_cd variable in pos2009 dataset :

       SRV: |
CHEMOTHERAP |
  Y SERVICE |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      8,638       86.38       86.38
          0 |      1,243       12.43       98.81
          1 |        100        1.00       99.81
          2 |         13        0.13       99.94
          3 |          6        0.06      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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