Frequencies for first 10,000 rows of prov1345 variable in pos1995 dataset :

 tech super |
          - |
 diagnostic |
      immun |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      9,774       97.74       97.74
          1 |        191        1.91       99.65
          2 |         29        0.29       99.94
          3 |          2        0.02       99.96
          4 |          3        0.03       99.99
          5 |          1        0.01      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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