Frequencies for first 10,000 rows of prov0830 variable in pos1993 dataset :

        lab |
directors - |
 doctorates |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      9,884       98.84       98.84
          1 |         98        0.98       99.82
          2 |         13        0.13       99.95
          3 |          3        0.03       99.98
          4 |          2        0.02      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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