Frequencies for first 10,000 rows of prov2210 variable in pos1999 dataset :

       srv: |
 laboratory |
 (clinical) |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      8,885       88.85       88.85
          0 |          9        0.09       88.94
          1 |        808        8.08       97.02
          2 |        227        2.27       99.29
          3 |         71        0.71      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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