Frequencies for first 10,000 rows of vyear variable in namcs1993 dataset :

    year of |
    visit - |
     last 2 |
     digits |      Freq.     Percent        Cum.
------------+-----------------------------------
         93 |     10,000      100.00      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 28 Mar 2016