Create the data set. REFLIB.STOCKS contains yearly highs and lows for the Dow Jones Industrial Average, and the dates of the high and low values each year. 
data reflib.stocks;
   input year @7  hdate date9. @15 high
              @24 ldate date9. @32 low;
   format hdate ldate date9.;
   datalines;
1955  30DEC55  488.40  17JAN55  388.20
1956  06APR56  521.05  23JAN56  462.35
...more data lines...
1994  31JAN94 3978.36  04APR94 3593.35
1995  13DEC95 5216.47  30JAN95 3832.08
;