Circular baby blanket

Hello everyone,
I was just wondering if anyone could tell me approximately how much yarn one of these circular baby blankets takes? I know you can just keep knitting till you like the size but I’m just looking for an approximate answer. Here it is…http://www.knitlist.com/00gift/round-baby-blanket.htm

Thanks everyone!

i used 5 skeins of Bernat Baby Boucle (204 yards each) on size 8’s for mine. it ended up being 39" in diameter.