Frequencies for first 10,000 rows of prov1570 variable in pos2007 dataset :

participati |
on medicare |
     opt/sp |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      9,861       98.61       98.61
          N |        135        1.35       99.96
          Y |          4        0.04      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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