Frequencies for first 10,000 rows of prov1345 variable in pos1991 dataset :

 tech super |
          - |
 diagnostic |
      immun |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      9,683       96.83       96.83
          1 |        262        2.62       99.45
          2 |         45        0.45       99.90
          3 |          4        0.04       99.94
          4 |          5        0.05       99.99
          5 |          1        0.01      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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