Frequencies for first 10,000 rows of prov2440 variable in pos1991 dataset :

       srv: |
  radiology |
(diagnostic |
          ) |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      8,770       87.70       87.70
          0 |         45        0.45       88.15
          1 |        951        9.51       97.66
          2 |        171        1.71       99.37
          3 |         63        0.63      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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