Frequencies for first 10,000 rows of prov2200 variable in pos1998 dataset :

       srv: |
 laboratory |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      8,007       80.07       80.07
          0 |      1,210       12.10       92.17
          1 |        128        1.28       93.45
          2 |        632        6.32       99.77
          3 |         23        0.23      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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