Dear tarun,  

St Stephan hostel are called residence and not hostel.It doesn't matter if you have 95% or 99% as the rule of the residence is that two fresher have to share the room in their first year. From second year onwards you are give separate rooms. So till then you have to share your room, you have no option. Otherwise you can take a PG outside if you want but it will be expensive then the St Stephan Residence.