Frequencies for first 10,000 rows of prov1250 variable in pos1991 dataset :

technicians |
-high sch + |
   training |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      9,953       99.53       99.53
          1 |         35        0.35       99.88
          2 |          9        0.09       99.97
          3 |          1        0.01       99.98
          4 |          1        0.01       99.99
          6 |          1        0.01      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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