Frequencies for first 10,000 rows of hmo variable in nhamcsed1998 dataset :

       does |
    patient |
  belong to |
    an hmo? |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |      2,303       23.03       23.03
          2 |      4,451       44.51       67.54
          3 |      3,040       30.40       97.94
          4 |        206        2.06      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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