Frequencies for first 10,000 rows of none variable in namcs1996 dataset :

       does |
    patient |
have - none |
     of the |
      above |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      4,462       44.62       44.62
          1 |      5,538       55.38      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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