**nobs = all nobs=last help you to create a logical variable called 'all' or 'last', it doesn't matter what you want to call it. If you don't create a newvariable using this logical variable, it will never show up. If you want to use it, you can create a new variable called 'totalpeople' and the results are same:

totalpeople=all

totalpeople=last

**************************************************;

data test1;

input x;

cards;

3.3

5

0.6

11

608

;

run;