BookScan numbers are showing this growth, as Brian Hibbs of Comic Book Resources explains in this article.

“As always, I strongly encourage you to look at the BookScan numbers on your own and make your own conclusions -- I'm trying to be balanced and fair, but, of course, I have huge bookshelves worth of biases I'm dragging around with me, and your analysis might be more correct than my own. Every year I write this and hope and pray that we'd get three or four competing analyses of the data dump, but that never happens. Maybe this year? (probably not).”

Read the complete text here.