Rank coming in decimal

[Srigyan]

I have getting this output by below code data, 

Col-1	Col-2	ranking
229ZO	5	5
229ZO	6	6
22BV6	1	2.5
22BV6	1	2.5
22BV6	1	2.5
22BV6	1	2.5

I am getting above ranking by below code, I am not expecting rank as 2.5, it should be 1 in all the case as it is based on col-2 and group by col-1.

code is

proc rank data= have out = want;
var col-2;by col-1;
ranks ranking;

run;

can someone tell me why this is coming as 2.5 and how to correct it.

[Astounding]

Add to the PROC RANK statement:

ties=low