Adding a new column to a sas table with the number of records in each group

[aalluru]

Suppose I have a SAS table as follows:

ID   Yr

A    2003

A    2004

A    2004

B    2003

B    2003

I would like to add a new column which has the number of occurrences of each ID as follows:

ID   Yr       Occurences

A    2003   3

A    2004   3

A    2004   3

B    2003   2

B    2003   2

Please advise on how I can do this

[novinosrin · Accepted solution]

data have;
input ID $   Yr;
cards;
A    2003

A    2004

A    2004

B    2003

B    2003
;

proc sql;
 create table want as
 select *, count(*) as occurences
 from have
 group by id
 order by id, yr;
quit;

[novinosrin]

data want;
 do _n_=1 by 1 until(last.id);
  set have;
  by id;
  occurences=sum(occurences,1);
 end;
 do _n_=1 to _n_;
  set have;
  output;
 end;
run;

[aalluru]

That worked perfectly. Thank you so much!