Frequencies for first 10,000 rows of prov6220 variable in pos2009 dataset :

       SRV: |
  OPTHALMIC |
    SURGERY |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      8,638       86.38       86.38
          0 |      1,212       12.12       98.50
          1 |        112        1.12       99.62
          2 |         24        0.24       99.86
          3 |         14        0.14      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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