I am a PhD student, and I live on about 60% or 70% of my scholarship (though my parents do still pay for e.g. my car insurance; if I also counted all the money my parents spend on me, it'd be higher, but probably still not close to 100% unless I'm forgetting lots of stuff). I picked “about 75%”.

(EDIT: Just noticed that the poll said “need to” -- well, I could in principle reduce my expenditures, but it wouldn't be anywhere near trivially easy for me to do so by a substantial amount.)