Frequencies for first 10,000 rows of hmo variable in nhamcsed1999 dataset :

       does |
    patient |
  belong to |
    an hmo? |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |      2,586       25.86       25.86
          2 |      4,149       41.49       67.35
          3 |      3,132       31.32       98.67
          4 |        133        1.33      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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