US DVD & Blu-ray sales fell 18% Y-o-Y in H1 2011

"According to details just released by the studio-backed Digital Entertainment Group (DEG), DVDs and Blu-ray discs dropped an elephantine 18.3 percent during the first half of this year.  Overall, first-half physical sales reached $3.9 billion.
That is the total for 'packaged goods,' though Blu-rays actually inched upward 10 percent.  Which means, DVDs are positively hemorrhaging as consumers increasingly shift towards Netflix, VOD, and kiosk rentals.  In fact, this is the first period in which newer formats outsold physical formats, an inflection point with an extremely bittersweet asterisk."

Source:  Data from DEG, reported by Digital Music News, 7th August 2011