Frequencies for first 10,000 rows of opthmlgy_srgry_sw variable in pos2002 dataset :

      spec: |
opthamology |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      9,212       92.12       92.12
          N |        412        4.12       96.24
          Y |        376        3.76      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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