Frequencies for first 10,000 rows of prov1280 variable in pos1995 dataset :

 tech super |
    - ba/bs |
   spec exp |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      9,960       99.60       99.60
          1 |         36        0.36       99.96
          2 |          3        0.03       99.99
          3 |          1        0.01      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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