(Click on charts for larger versions.)
Number is the issue number published during that month (cover dates are given, not on-sale dates). They are grouped by 'wave.' You'll note in the totals that for most months they did indeed publish 52 comics as part of the DCnU, except for Sep 2012 when Batman Incorporated skipped a month due to thematic sensitivity due to the theater shootings; Nov 2012 during Zero Month when they published #0 issues for three cancelled series; and the upcoming Apr 2013, apparently because the new Constantine series won't be ready to launch in time.
Here's the same table/chart, but with Diamond North America sales figures (in thousands) in place of the issue numbers:
(Sales figures include re-order activity and additional printings and are adjusted for returnability as per the calculations over at The Beat.)