Frequencies for first 10,000 rows of prov6210 variable in pos2006 dataset :

       srv: |
   magnetic |
  resonance |
    imaging |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      8,710       87.10       87.10
          0 |      1,204       12.04       99.14
          1 |         52        0.52       99.66
          2 |         30        0.30       99.96
          3 |          4        0.04      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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