Frequencies for first 10,000 rows of vyear variable in nhamcsopd1992 dataset :

    Year of |
    visit - |
     last 2 |
     digits |      Freq.     Percent        Cum.
------------+-----------------------------------
         91 |        842        8.42        8.42
         92 |      9,158       91.58      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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