_n_ and proc transpose

we have one data set like this:

Obs	list	status	var	relief
1	a	60	100	20
2	b	60	100	20
3	a	60	100	30
4	b	60	100	30

want to get a new data set like this:

Obs	status	var	relief	relief1	relief2
1	60	100	20	a	b
2	60	100	30	a	b

data have;
length list $1;
input status var relief list;
cards;
60 100 20 a
60 100 20 b
60 100 30 a
60 100 30 b
;

data have;
set have;
if _n_ eq 1 then id=1; /*_n_ calculates the occurrence of list*/
else if mod(_n_,2) then id+1;
run;

proc transpose data=have out=want (drop=id _:
rename=(col1=relief1
col2=relief2));
by id status var relief;
var list;
run;