Frequencies for first 10,000 rows of prov2200 variable in pos2002 dataset :

       srv: |
 laboratory |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      7,717       77.17       77.17
          0 |      1,273       12.73       89.90
          1 |        143        1.43       91.33
          2 |        838        8.38       99.71
          3 |         29        0.29      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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