Create a yearly file data set from 2 years

[vapodaca11]

I am trying to create a yearly observation between 20 years that expands beyond the years. 

What I have

Location       Year                Num

A                   1980              123

A                   2010              496

B                   1980             1846

B                   2010             1776

What I want is to create a yearly observation while retaining the Location but not the Num variable. Specifically I need to go from 1980 to 2012. 

What it should look like:

Location       Year                Num

A                   1980              123

A                   1981               

A                   ...... 

A                   2009

A                   2010              496

A                   2011           

A                   2012

[Astounding]

Unfortunately, it takes a few steps.  But they're all short:

data years;
   do year = 1980 to 2012;
      output;
   end;
run;

proc sql;
   create table locations as select distinct location from have;
   create table shell as select * from locations, years order by location, year;
quit;

data want;
   merge shell have;
   by location year;
run;

It's untested code, so see if it works for you.

****** Corrected ... thanks @VDD 

[VDD]

you will need a comma in the by statement.

create table shell as select * from locations, years order by location year;

should be

create table shell as select * from locations, years order by location, year;