Frequencies for first 10,000 rows of prov1280 variable in pos1993 dataset :

 tech super |
    - ba/bs |
   spec exp |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      9,952       99.52       99.52
          1 |         43        0.43       99.95
          2 |          4        0.04       99.99
          3 |          1        0.01      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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