以下的程序：

libname learn 'E:\sas\learning';
data learn.perm;
input ID :$3.
      Gender : $1.
   DOB : mmddyy10. Height Weight;
label DOB='Date of Birth';
      Height='Height in inches';
   Weight='Weight in pounds';
format DOB date9.;
datalines;
001 M 10/21/1946 68 150
002 F 5/26/1950 63 122
003 M 5/11/1981 72 175
004 M 7/4/1983 70 128
005 F 12/25/2005 30 40
;
run;
proc print data=learn.perm;
run;

结果为什么会是这样：

      The SAS System          13:17 Sunday, October 10, 2008   6

                        Obs    ID     Gender          DOB    Height    Weight

                         1     001      M       21OCT1946       .         .
                         2     002      F       26MAY1950       .         .
                         3     003      M       11MAY1981       .         .
                         4     004      M       04JUL1983       .         .
                         5     005      F       25DEC2005       .         .

后面两个没有输入进去，请问是为什么啊？