Frequencies for first 10,000 rows of hmo variable in namcs1998 dataset :

       does |
    patient |
  belong to |
    an hmo? |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |      2,981       29.81       29.81
          2 |      6,138       61.38       91.19
          3 |        803        8.03       99.22
          4 |         78        0.78      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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