Frequencies for first 10,000 rows of refunins variable in namcs2004 dataset :

 difficulty |
  referring |
  uninsured |
    pat for |
       cons |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |        300        3.00        3.00
          1 |      1,560       15.60       18.60
          2 |      1,728       17.28       35.88
          3 |      1,054       10.54       46.42
          4 |      3,140       31.40       77.82
          5 |      2,218       22.18      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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