Frequencies for first 10,000 rows of prov2200 variable in pos1993 dataset :

       srv: |
 laboratory |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      8,478       84.78       84.78
          0 |      1,050       10.50       95.28
          1 |         81        0.81       96.09
          2 |        377        3.77       99.86
          3 |         14        0.14      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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