Frequencies for first 10,000 rows of prov6220 variable in pos2006 dataset :

       srv: |
  opthalmic |
    surgery |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      8,710       87.10       87.10
          0 |      1,232       12.32       99.42
          1 |         49        0.49       99.91
          2 |          5        0.05       99.96
          3 |          4        0.04      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 26 Jan 2016