Frequencies for first 10,000 rows of prov1310 variable in pos1991 dataset :

 tech super |
 - clinical |
  chemistry |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      9,651       96.51       96.51
          1 |        278        2.78       99.29
          2 |         53        0.53       99.82
          3 |          7        0.07       99.89
          4 |          5        0.05       99.94
          5 |          3        0.03       99.97
          6 |          2        0.02       99.99
          9 |          1        0.01      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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