See also this recent
Nature paper about a primeval galaxy with a Star Formation Rate of several hundred solar masses per annum.
www.nature.com/nature/journal/v502/n7472/full/nature12657.html
You can access the first page, for free, using "ReadCube"
(a related observation is that
most of the stars in the bulge component of our own Galaxy formed 10-12 billion years ago )
(the current SFR of the Milky Way is about 2 solar masses per annum, according to a recent weighted average. This is about typical for a large spiral galaxy. )
(NGC 253 has about 3 or 4 solar masses in stars, right near to its centre, forming every year, due to a circum-nuclear starburst. )