The Graphic Books chart has 147 new items and 153 backlist items, give or take, depending on whether you choose to count the movie cover edition of KINGSMAN or the new edition of DRAGONLANCE CHRONICLES (previously from Devil's Due, now from IDW) as new or backlist. I counted both of those as new.
The top 10 backlist items were:
SAGA TP VOL 04
SAGA TP VOL 01
WALKING DEAD TP VOL 01 DAYS GONE BYE
CIVIL WAR TP
SAGA TP VOL 02
SEX CRIMINALS TP VOL 01
YU-GI-OH 5DS GN VOL 07
BATMAN TP VOL 01 THE COURT OF OWLS (N52)
SAGA TP VOL 03
WICKED & DIVINE TP VOL 01 THE FAUST ACT
Over on the Comics chart, a few anomalies with Star Wars still having a big effect with its recent publisher shift, now accounting for four of the top 10. Presumably this will continue through the year as the hype machine for the the next movie grinds on and more comics directly dealing with the movie (preludes, adaptations and probably eventually follow-ups) come out. DC had kind of an odd month, with several of their top books (most notably BATMAN and JUSTICE LEAGUE) running late and missing the month. It'll be quite a while before there's anything approaching a normal month again, with DC's CONVERGENCE and subsequent launch of almost two dozen new books and Marvel's SECRET WARS and whatever comes after that both taking up the next few months.
Second issues averaged a drop of 37%, although that somewhat unfairly includes the 97.9% drop of ORPHAN BLACK #2 after the Loot Crate propelled half-million sales of #1. Without that the #2 drop was around 34%, which is close to normal.