At the start of 2013 it looked like 10M, which led to a belief that nobody would get miners made on 28nm for a year, however, due to huge overbuilding of fab capacity, 28nm got suddenly cheap, not quite sure how cheap but by beginning of Q3 I think ~2M seemed to be a reasonable guesstimate, fire sale on 28nm. Which is probably what encouraged all sorts of clowns to take a punt.