Frequencies for first 10,000 rows of psychoph variable in nhamcsopd1998 dataset :

psycho-phar |
macotherapy |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      9,870       98.70       98.70
          1 |        130        1.30      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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