Nas and Zac Brown Band battle for No. 1 on low-selling Billboard 200

Whether it”s summer doldrums or the focus on the Olympics, album sales fall off a cliff on next week”s Billboard 200.

With a few day left to go before Nielsen SoundScan”s tally closes Sunday night, this week”s No. 1, Nas”s “Life Is Good” and last week”s chart topper, Zac Brown Band”s “Unchanged” are too close to call for the pole position. Either way, neither one is selling more than 50,000, according to Hits Daily Double, which will mean that whoever is No. 1 next week holds the dubious distinction of the lowest total so far in 2012 for a No. 1.

There are only two bows in the Top 10. Gaslight Anthem”s major label debut, “Handwritten,” could come in as high at No. 3 or as low as No. 5: right now, “Handwritten,” Kidz Bop Kids” “Kidz Bop 22,” and Justin Bieber”s “Believe” are all looking like they will move between 35,000-40,000 units each.

The other debut belongs to Passion Pit”s “Gossamer,” which will likely launch at No. 9 on sales of up to 32,000.

Just as the top 5 are too close to call, the same goes for No. 6-8. One Direction”s “Up All Night,” Adele”s “21,” and Frank Ocean”s “Channel Orange” are all trending toward sales of between 30,000-35,000.

Likely to land at No. 10 is Maroon 5″s “Overexposed” with sales of 24,000-27,000.

So if anyone”s paying close attention: If the No. 1 title sells on the low end of the projection at 45,000 and Maroon 5 sells at the high end for No. 10 at 27,000, that means only 18,000 units separate No. 1 from No. 10. I cannot imagine another scenario where that has ever been the case.