Frequencies for first 10,000 rows of prov2200 variable in pos2001 dataset :

       srv: |
 laboratory |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      7,837       78.37       78.37
          0 |      1,238       12.38       90.75
          1 |        134        1.34       92.09
          2 |        766        7.66       99.75
          3 |         25        0.25      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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