Frequencies for first 10,000 rows of psychoph variable in nhamcsopd1999 dataset :

psycho-phar |
macotherapy |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      9,811       98.11       98.11
          1 |        189        1.89      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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