At the mid-point of 2008, U.S. album sales stand at an 11% decline when compared to the same period a year ago. Though not as precipitous a drop as the one recorded in the first half of 2007 (15.1%), this year's first half tally is 204.6 million units, according to Nielsen SoundScan. That’s compared to 229.8 million units scanned in the first six months of 2007.

That drop is fueled largely by the 16.3% decrease in CD sales; digital albums posted a 34.4% increase to 31.6 million units and now account for 15.4% of album sales. Digital tracks continue to be a bright spot, growing 30% to 532.7 million units in the six month period ended June 29. That compares with the 417.3 million recorded in the six-month period ended July 1, 2007.

At this point, the top-selling album was Lil Wayne's "Tha Carter III," with 1.5 million scans; followed by Jack Johnson's "Sleep Through The Static," at 1.2 million; and Mariah Carey's "E=MC2," with 1.1 million units.

The best selling tracks were led by Leona Lewis' "Bleeding Love," at 2.6 million units; followed by Flo Rida's "Low," featuring T-Pain with 2.4 million units; and Jordan Sparks "No Air" duet with Chris Brown, which clocked 2.1 million units.

Looking at album market share, the Universal Music Group continues to dominate the U.S. industry with a 31.2%. But that's down from the 31.5% the company posted in the first six months of 2007. Sony BMG Music Entertainment also lost market share. The company finished the first half with 24.8%, down from the 25.3% it had in the corresponding period last year. Coming in third in the rankings, WEA tallied 20.8% share in the first six months of the year, up nearly one percentage point from the 20% it recorded in the first half of last year. EMI’s market share fell to 9.4% from the 10.4% it had last year.

Like WMG, the indies where the only other group to gain market share, finishing collectively with 13.9%, up from the 12.9% the group garnered in the first half of last year.