Frequencies for first 10,000 rows of prov0770 variable in pos1991 dataset :

cytotechnol |
ogists-6 mo |
      train |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      9,993       99.93       99.93
          1 |          5        0.05       99.98
          2 |          1        0.01       99.99
          3 |          1        0.01      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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