Frequencies for first 10,000 rows of optmtrc_srvc_cd variable in pos1994 dataset :

       srv: |
 optometric |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      8,940       89.40       89.40
          0 |        918        9.18       98.58
          1 |         73        0.73       99.31
          2 |         61        0.61       99.92
          3 |          8        0.08      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 17 May 2017