Frequencies for first 10,000 rows of hmo variable in namcs2000 dataset :

       does |
    patient |
  belong to |
    an hmo? |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |      3,090       30.90       30.90
          2 |      5,649       56.49       87.39
          3 |      1,077       10.77       98.16
          4 |        184        1.84      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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