Frequencies for first 10,000 rows of OPTHLMC_SRGY_SRVC_CD variable in pos2011 dataset :

   Services |
  Provided: |
 Ophthalmic |
    Surgery |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      8,614       86.14       86.14
          0 |      1,192       11.92       98.06
          1 |        150        1.50       99.56
          2 |         24        0.24       99.80
          3 |         20        0.20      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 19 Apr 2019