Frequencies for first 10,000 rows of thorc_srgry_sw variable in pos1993 dataset :

      spec: |
   thoracic |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      9,608       96.08       96.08
          N |        368        3.68       99.76
          Y |         24        0.24      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 17 May 2017