Frequencies for first 10,000 rows of hmo variable in nhamcsopd1997 dataset :

       does |
    patient |
  belong to |
    an hmo? |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |      2,083       20.83       20.83
          2 |      5,946       59.46       80.29
          3 |      1,874       18.74       99.03
          4 |         97        0.97      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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