Frequencies for first 10,000 rows of prov1275 variable in pos1993 dataset :

 tech super |
    - ba/bs |
  chemistry |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      9,990       99.90       99.90
          1 |          8        0.08       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